Guido Caspari

Intracardiac Echocardiography Is Superior to Conventional Monitoring for Guiding Device Closure of Interatrial Communications

Background—This study sought to test whether intracardiac echocardiography (ICE) is superior to conventional monitoring in guiding device closure of interatrial communications (atrial septal defect [ASD] and patent foramen ovale [PFO]). Methods and Results—Forty-four patients undergoing device closure of ASD (n=6) or PFO (n=38) were randomized to have the procedure guided by either ICE (group 1; n=22) or by transesophageal echocardiography (TEE) (group 2; n=22). All interventions were completed successfully. In 1 patient from group 2, atrial fibrillation occurred 1 day after device implantation; the patient was successfully cardioverted on the next day. There were no other complications. Fluoroscopy time (FT) (6.0±1.7 minutes versus 9.5±1.6 minutes;P <0.0001) as well as procedure time (PT) (33.4±4.7 minutes versus 37.8±5.6 minutes;P <0.01) were shorter in group 1 than in group 2. Group 2 patients required general anesthesia without (n=19) or with endotracheal intubation (n=3). In contrast, ICE allowed continuous monitoring of the whole procedure, including balloon sizing before device closure, without sedation. Conclusions—ICE is a safe tool to guide device closure of PFO and ASD. Supine patients tolerate ICE better than TEE. ICE reduces FT and PT. ICE seems to be advantageous, especially when long continuous or repeated echocardiographic viewing is required.

Comparison of Myocardial Perfusion Reserve Before and After Coronary Balloon Predilatation and After Stent Implantation in Patients With Postangioplasty Restenosis

BACKGROUND Stents provide a scaffold for coronary arteries after angioplasty and inhibit elastic recoil. METHODS AND RESULTS In 25 patients with postangioplasty restenosis of the left anterior descending artery, ECG-gated digital subtraction coronary angiograms were recorded at baseline and during hyperemia (12 mg papaverine IC) before and after balloon predilatation (PTCA), after implantation of a Palmaz-Schatz stent, and after 6 months. Densitometric evaluation revealed different time and density parameters to calculate two definitions of myocardial perfusion reserve (MPR1 and MPR2) and maximum flow ratio (MaxFR). Poststenotic MPR1 increased from 1.57 +/- 0.14 to 2.59 +/- 0.86 after PTCA and to 3.10 +/- 0.41 after stenting, with 2.90 +/- 0.65 at follow-up (ANOVA, P < .05), while reference MPR1 remained unchanged at 3.10 +/- 0.40. Poststenotic MPR2 increased from 1.36 +/- 0.28 to 2.50 +/- 1.20 and to 3.40 +/- 0.58, respectively, with 3.20 +/- 0.92 at follow-up (ANOVA, P < .05), while reference MPR2 remained unchanged at 3.40 +/- 0.60. MaxFR was 2.13 +/- 0.53 after PTCA, elasticity 2.83 +/- 0.35 after stenting, and 2.73 +/- 0.58 at follow-up (ANOVA, P < .05). A good correlation was found between minimal stenotic luminal diameter and MPR1 or MPR2 (r = .87 and r = .94) and between luminal gain and MaxFR (r = .75). A negative correlation was measured between recoil and MPR1, MPR2, and MaxFR (r = -.80, r = -.86, and r = -.83). At follow-up, a steeper correlation was found between MPR and minimal stenosis diameter (MPR1: slope, 0.52 versus 0.91; MPR2: slope, 1.48 versus 1.95) and between MaxFR and net lumen gain (slope, 0.78 versus 1.27). CONCLUSIONS Coronary stent implantation in patients with postangioplasty restenosis normalized poststenotic myocardial perfusion immediately as a result of a larger postprocedural lumen and a more pronounced inhibition of elastic recoil. After 6 months this benefit was sustained despite progressive lumen loss.

Changes in QRS voltage in cardiac tamponade and pericardial effusion: reversibility after pericardiocentesis and after anti-inflammatory drug treatment

OBJECTIVES The goal of this study was to define the association between low QRS voltage and cardiac tamponade or pericardial effusion and to assess the reversibility of low QRS voltage after therapeutic procedures. BACKGROUND It is unclear whether low QRS voltage is a sign of cardiac tamponade or whether it is a sign of pericardial effusion per se. METHODS In a prospective study design, we recorded consecutive 12-lead electrocardiograms and echocardiograms in 43 patients who were referred to our institution for evaluation and therapy of a significant pericardial effusion. Cardiac tamponade was present in 23 patients (53%). Low QRS voltage (defined as maximum QRS amplitude <0.5 mV in the limb leads) was found in 14 of these 23 subjects (61%). Nine of these 14 patients were treated by pericardiocentesis (group A). Five patients received anti-inflammatory medication (group B). Group C consisted of nine patients with pericarditis and significant pericardial effusion who had no clinical evidence of tamponade. RESULTS In group A, low QRS voltage remained largely unchanged immediately after successful pericardiocentesis (0.36 +/- 0.17 mV before vs. 0.42 +/- 0.21 mV after, p = NS), but QRS amplitude recovered within a week (0.78 +/- 0.33 mV, p < 0.001). In group B, the maximum QRS amplitude increased from 0.40 +/- 0.20 mV to 0.80 +/- 0.36 mV (p < 0.001) within six days. In group C, all patients had a normal QRS amplitude initially (1.09 +/- 0.55 mV) and during a seven-day follow-up (1.10 +/- 0.56 mV, p = NS). CONCLUSIONS Low QRS voltage is a feature of cardiac tamponade but not of pericardial effusion per se. Our findings indicate that the presence and severity of cardiac tamponade, in addition to inflammatory mechanisms, may contribute to the development of low QRS voltage in patients with large pericardial effusions.

Intracardiac and intraluminal echocardiography: indications and standard approaches.

In particular clinical scenarios, transthoracic and transoesophageal echocardiography (TEE) have limitations. This study sought to test if intracardiac and intraluminal echocardiography (ICLE), including 2-D, M-mode and Doppler analysis with a miniaturised, multiple-frequency transducer-tipped catheter, is suitable for assessing distinct cardiac and vascular disorders. ICLE was employed in 10 animals using 6 standard approaches. In 12 patients undergoing device closure of patent foramina ovalia (PFO) (n = 6) or atrial septal defects (ASD) (n = 3), or aortic stent implantation (n = 3), interventional procedures were guided by ICLE and, for comparison, also by TEE. ICLE provided enhanced diagnostic information on the aorta, cardiac valves, main pulmonary vessels and both atria and, therefore, added to the diagnostic spectrum of TEE. Especially for guiding interventional procedures (e.g., device closure of atrial septal defects and patent foramina ovalia), ICLE was shown to be helpful. Compared with the conventional approach, the technique reduced fluoroscopy time for device closure procedures: 6.5 min vs. 8.9 min, p < 0.0011. With the patient in a supine position, ICLE was better tolerated than TEE. Complications did not occur, either with ICLE or with TEE. In conclusion, ICLE adds to conventional echocardiography and promises to become a clinical alternative for guiding interventional procedures.

X-ray densitometry for the measurement of regional myocardial perfusion

Abstract The evaluation of regional myocardial blood flow (RMBF) during cardiac catheterization is of particular diagnostic interest. The purpose of this investigation was to validate x-ray densitometric parameters for the evaluation of RMBF.In five anesthetized dogs, arterial flow in the circumflex coronary artery was measured continuously with an electromagnetic flowmeter, and RMBF was determined by colored microspheres. Five different perfusion levels were created by mechanical obstruction of the coronary artery or by intravenous infusion of adenosine. At each steady-state perfusion level, digital subtraction coronary angiograms were obtained for densitometric analysis.Results documented a close correlation between the related time parameters 1/Mean Transit Time (1/MTT, r2 = 0.969), and 1/Rise Time (1/RT, r2 = 0.965) and RMBF over a wide range between 0.36 ml/(min · g) and 11.16 ml/(min · g). Maximum myocardial contrast density (Imax) also showed a good, but inverse correlation (r2 = 0.889) with RMBF and, therefore, did not reflect vascular volume. Contrast medium Appearance Time (AT) showed no correlation to RMBF (r2 = 0.017). Repeat densitometric measurements for different perfusion levels revealed a good reproducibility for MTT (accuracy: 0.001 s; precision: 0.447 s or 6.7%) and RT (accuracy: 0.014 s; precision: 0.202 s or 10.4%), while AT (accuracy: 0.072 s; precision: 0.420 s or 68.5%) and Imax (accuracy: 0.022 GL; precision: 1.197 GL or 44.5%) showed substantial variation. Myocardial perfusion reserve (MPR) calculated from RT (r2 = 0.90) or MTT (r2 = 0.94) showed better correlations to RMBF reserve than MPR calculated from AT (r2 = 0.04).In conclusion, only 1/MTT and 1/RT showed a good reproducibility and a close correlation to RMBF. Therefore, only these parameters can be recommended for calculations of RMBF and its reserve under clinical conditions.

Contrast echocardiography for assessment of myocardial perfusion

SummaryIt has been suggested that the myocardial perfusion can be qualitatively and quantitatively assessed by different ultrasound contrast techniques. It has been reported that the intracoronary or intraaortic administration of the ultrasound contrast agents can be used to visualize perfusion defects or to analyze the coronary flow reserve.The perfusion analysis after intracoronary injection of ultrasound contrast agents seems to be established, but there are a lot of open questions. A topographic (qualitative) perfusion analysis with visualization of perfusion defects and perfusion areas or analysis of collaterals has been demonstrated. A quantitative analysis of myocardial blood flow has been described but the existing studies are inconsistent. It is not known which parameters of the contrast wash-out curves should be used for perfusion analysis and if the Stewart-Hamilton curve analysis can be transfered to all ultrasound contrast agents as a model for quantitative myocardial blood flow assessment. The development of the transpulmonary contrast agents for echocardiographic evaluation of left ventricular cavity has the impact for myocardial perfusion imaging. The increase of myocardial intensity does not mean that a qualitative or quantitative perfusion analysis can be clinically used. In this field we have to differentiate between the possibilities of qualitative discrimination of perfusion defects and quantitative perfusion (myocardial blood flow) analysis. The different scanning conditions, the poor transthoracic ultrasound window and insufficient enhancemant of the myocardial intensity make it problematic to quantify the myocardial perfusion. At the moment myocardial intensity will be increased after intravenous injection of transpulmonary contrast agents, but the value for perfusion analysis has not been shown.New ultrasound technologies such as second harmonic imaging, power-mode and raw data analysis have to show the clinical importance of these techniques for perfusion analysis in daily clinical routine. The open questions of the perfusion analysis by contrast echocardiography will be discussed in this review article.ZusammenfassungIn den bisher publizierten Studien wird beschrieben, daß die Myokardperfusion mittels der intrakoronaren Kontrastechokardiographie (ICE) quantitativ und qualitativ beurteilt werden kann. Es wird vor allem postuliert, daß die intrakoronare oder die intraaortale Applikation von Ultraschallkontrastmitteln zur Beurteilung von Perfusionsdefekten und zur Einschätzung der koronaren Flußreserve herangezogen werden kann. Die Analyse der Perfusion nach intrakoronarer Injektion von Ultraschallkontrastmitteln scheint etabliert zu sein, es bleiben jedoch einige offene Fragen. Es wurde demonstriert, daß die topographische (qualitative) Darstellung der myokardialen Perfusionsdefekte, der perfundierten Areale oder die Funktionsanalyse der Kollateralen möglich ist. Die Darstellung des „no-reflow”-Phänomens mittels der ICE hat prognostische Bedeutung bei Patienten mit angiographisch erfolgreicher Reperfusion nach Thrombolyse oder PTCA. Bei Patienten ohne eine Perfusion der Mikrozirkulation (fehlender Kontrasteffekt) bei der Darstellung mittels der ICE ist in diesen Bezirken die Prognose bezüglich einer Erholung der kontraktilen Funktion reduziert, obwohl angiographisch die Reperfusion erfolgreich war.Eine quantitative Analyse des myokardialen Flusses wird ebenfalls beschrieben, die Ergebnisse der Studien sind jedoch nicht einheitlich. Es ist nicht eindeutig klar, welche Parameter der Auswaschkurven der Kontrastmittel zur quantitativen Analyse der Perfusion herangezogen werden sollen und ob die Stewart-Hamilton Kurvenanalyse auf jedes Ultraschallkontrastmittel übertragen und angewendet werden kann. Auch die Möglichkeit der Analyse der myokardialen Flußreserve mittels der Kontrastechokardiographie wird von den Arbeitsgruppen unterschiedlich beurteilt.Die Entwicklung der transpulmonalen Ultraschallkontrastmittel für die echokardiographische Untersuchung der linken Herzkammer hat prinzipiell das Potential der nichtinvasiven Perfusionsanalyse. Es ist jedoch nicht gleichbedeutend, daß ein Anstieg der myokardialen Intensität nach der intravenösen Applikation eines transpulmonalen Echokontrastmittels eine klinisch zuverlässige und ausreichende qualitative und quantitative Analyse der myokardialen Perfusion erlaubt. Prinzipiell sollte differenziert werden zwischen der Möglichkeit einer qualitativen Darstellung der Perfusionsdefekte und der Möglichkeit der quantitativen Erfassung des myokardialen Blutflusses. Eine zuverlässige qualitative (topographische) Analyse von Perfusionsdefekten mittels der intravenösen Kontrastmittelapplikation ist in der Zukunft bei der weiteren Entwicklung der Ultraschalltechnologie nicht ausgeschlossen.Unterschiedliche Beschallungssituation, breite Streuung der Intensitätswerte, eingeschränktes Ultraschallfenster bei der transthorakalen Echokardiographie und nicht ausreichende Anhebung der myokardialen Intensität erschweren aber sowohl die qualitative und noch mehr die quantitative Analyse der myokardialen Perfusion mittels der intravenösen Kontrastechokardiographie.Die intravenöse Gabe von lungengängigem Echokontrastmittel kann vorerst klinisch zur verbesserten Erkennung der Endokard-Blut-Grenze und zur reproduzierbaren quantitativen Erfassung der linksventrikulären Funktion eingesetzt werden (vor allem in Kombination mit der Second-Harmonic-Technik). Bei der Doppler-Echokardiographie können die transpulmonalen Echokontrastmittel zur Signalverstärkung verwendet werden.Die reproduzierbare, topographische (qualitative) Analyse der myokardialen Perfusionsverteilung bleibt ein wichtiger unbestrittener Vorteil der intrakoronaren Kontrastechokardiographie.Zum jetzigen Zeitpunkt ist es zwar möglich, die Intensität der myokardialen Darstellung mittels intravenöser Applikation eines lungengängigen Echokontrastmittels anzuheben, doch die klinische Wertigkeit dieses Phänomens bezüglich einer Perfusionsmessung wurde bisher nicht gezeigt. Neue Ultraschalltechnologien wie Second-Harmonic-Imaging, Power-Mode und die Rohdatenanalyse müssen ebenfalls in der Zukunft ihre klinische Bedeutung bezüglich der Perfusions-analyse in der täglichen Praxis zeigen.

High-volume nonionic dimeric contrast medium: First experiences during complex coronary interventions

Interventional cardiology is a rapidly developing field of medicine with annually increasing numbers of coronary interventions. Especially through the development of alternative techniques for coronary angioplasty, new indications have been found and more difficult lesions are tackled. Inevitably, such complex interventions are time-consuming and require high amounts of contrast medium. Newer, mostly nonionic agents have been developed with improved tolerability as well as fewer cardiac and renal side effects due to their nonionic, hydrophilic structure, and their osmolality isotonic to plasma. This study sought to investigate the effects of high-volume nonionic, dimeric contrast medium during coronary interventions with special emphasis on renal and hemodynamic side effects during routine hospital stays. Retrospectively, 25 consecutive patients (age 56 +/- 10 yr) with normal renal and cardiac function receiving > 500 ml of the nonionic dimeric contrast medium iodixanol during complex coronary interventions were analyzed. The analysis was based on serum creatinine levels 1 day before and 2 days after contrast medium administration for the monitoring of renal function. Additionally, heart rate and left ventricular pressures were evaluated before and after left ventricular angiography. Mean serum creatinine rose from 0.9 +/- 0.2 mg/dl to 1.1 +/- 0.2 mg/dl (P < 0.05) after 2 days of coronary intervention. Heart rate, left ventricular systolic pressure, and left ventricular end-diastolic pressure did not change significantly. No major side effects were encountered in the short follow-up period of 2 days. Based on this retrospective analysis, high-volume nonionic, dimeric contrast medium administration in patients without preexisting renal insufficiency is associated with little impairment of renal function, and has only minor hemodynamic and general side effects. Iodixanol 320 mg I/ml is well-tolerated and effective for the use of cardioangiography. Given the limitations of this retrospective analysis, future prospective studies should systematically address the effects of high-volume contrast medium administration in otherwise healthy patients as well as in high-risk patients undergoing coronary interventions.

Kontrastmittelechokardiographisch gesteuerte Perikarddrainage

ZusammenfassungDie operative Perikardiotomie und die ungesteuerte perkutane Punktion weisen eine vergleichsweise hohe Letalitäts- und Komplikationsrate auf. Mit der Einführung der echokardiographisch gesteuerten Perikardpunktion konnten die Komplikationsraten entscheidend gesenkt werden.Die durch unsere Arbeitsgruppe integrierte kontrastmittelgesteuerte echokardiographische Lagekontrolle hat sich bei 126 mit dieser Methode konsekutiv behandelten Patienten als wertvolle zusätzliche Maßnahme zur Vermeidung von Komplikationen erwiesen. Es trat keine klinisch relevante Komplikation auf. Ein intraperikardial eingebrachter Drainagekatheter (Pigtail) blieb bis zur echokardiographischen Kontrolle, jedoch nicht länger als 48 Stunden, in situ, um das Infektionsrisiko zu minimieren. Die eigenen Erfahrungen bestätigen, dass auch bedeutsame Rezidivergüsse wiederholt punktiert werden können. Allerdings kann der Katheter selbst einen serösen Reizerguss induzieren, der jedoch nach Katheterentfernung sistiert.Die echokardiographisch mittels Kontrastmittel gesteuerte Perikardpunktion und -drainage können heute als Goldstandard gelten, da sie ein komplikationsarmes, effektive und kostengünstiges Verfahren sind.AbstractThe most effective treatment for pericardial effusion and cardiac tamponade is removal of the pericardial fluid. Surgical pericardiotomy is associated with high mortality and morbidity. Similarly, subcostal percutaneous blind pericardiocentesis was reported to have unacceptably high mortality and complication rates. Major complications associated with blind needle punctures are right heart penetration, hemopericardium, puncture of the coronary arteries, liver and lung bleeding. Even under fluoroscopic guidance and electrocardiographic needle monitoring high complication rates persist. Pericardial drainage has been often inadequate, with frequent recurrences of significant pericardial effusions. Two-dimensional echocardiographically guided pericardiocentesis is reported to improve efficacy and safety of percutaneous puncture. Moreover, it allows immediate verification of the procedural success. We evaluated the efficacy and safety of an echocardiographically guided contrast agent controlled pericardiocentesis.This is a retrospective, descriptive study on 126 consecutive patients who underwent percutaneous pericardiocentesis at the University Hospital Essen, Germany, from 1995 to June 2000. There were 51 women (41%) and 75 men (55%) with a mean age of 52 ± 14 years. Standard techniques for quantification of pericardial effusion were used. Depending on the localization of the pericardial effusion an apical or subxiphoidal approach was chosen. The puncture was performed under echocardiographic guidance and the position of the needle was controlled by injection of contrast agent. Over a long guidewire a pigtail catheter was inserted through a sheath for further drainage of pericardial fluid. The catheter was removed after a maximum of 48 hours to avoid infection of the pericardial cavity.An apical approach was chosen in 98 patients (78%), a subcostal in 28 patients (22%). The procedure was successful in 99% of the attempts. No death or clinical complication occurred. The maximal pericardial diameter measured by two-dimensional echocardiography was 32 ± 16 mm before and 5,3 ± 2 mm after drainage. The calculated pericardial effusion was 657 ± 342 ml. A fluid volume of 605 ± 342 ml could be drained. In all patients a pericardial catheter was placed for 1.4 ± 0.8 days. Recurrence of pericardial effusion occurred in 18 patients (14%). Of these, 15 patients underwent repeated successful pericardiocentesis (2.5 ± 0.8), and 3 patients were referred to surgical pericardiotomy.Pericardiocentesis under echocardiographic contrast agent guidance is a safe, successful and cost effective procedure for diagnostic and therapeutic drainage of pericardial effusion. Two-dimensional echocardiography allows localization of the optimal puncture site as well as the quantification of the effusion depth. The injection of contrast agents into the pericardial cavity improves the safety and accuracy of the procedure. Even recurrent pericardial effusions can be treated successfully.

Antiischämische Wirkung von Verapamil im Rahmen einer interventionellen Rekanalisation

ZusammenfassungWir berichten über einen 46jährigen Patienten mit instabiler Angina pectoris und angiographischem Nachweis eines Ramus-circumflexus-Verschlusses. An der Stelle einer Plaqueruptur war es zu einem thrombotischen Verschluß des Gefäßes gekommen. Mittels PTCA konnte das Gefäß wiedereröffnet und eine bestehende Dissektion mit Stentimplantationen beseitigt werden. Trotz eines morphologisch optimalen Ergebnisses und wiederholter Nitroglyceringabe fiel die Flußgeschwindigkeit in Ruhe von einem Ausgangswert von 16 cm/s über 11 cm/s nach PTCA auf 8,4 cm/s nach Stentimplantation. Bei kaum beeinflußter maximaler Blutflußgeschwindigkeit ergab sich aufgrund dieses langsamen Blutflusses in Ruhe („Slow-flow”-Phänomen) nie eine pathologische koronare Flußgeschwindigkeitsreserve. Erst die intrakoronare Applikation von 1 mg Verapamil führte zu einer anhaltenden Steigerung des Ruheblutflusses (17 cm/s), gleichzeitig gingen ischämietypische ST-Strecken-Senkungen im EKG zurück. Auch im nichtbehandelten RIVA wurde eine Steigerung der Blutflußgeschwindigkeit von 10 cm/s auf 25 cm/s beobachtet. Wir führen die mit der Anzahl der Manipulationen sinkende Blutflußgeschwindigkeit in Ruhe auf Mikrozirkulationsstörungen durch eine zunehmende α-adrenerge Vasokonstriktion, auf die Freisetzung vasoaktiver Substanzen und auf periphere Mikroembolien zurück. Erst durch die Gabe des unspezifisch antiadrenerg wirkenden Calciumantagonisten Verapamil konnte das „Slow-flow”-Phänomen beseitigt werden, während sich parallel dazu die ischämietyischen ST-Strecken-Veränderungen zurückbildeten. Die grenzwertig niedrige Flußgeschwindigkeit im nichtbehandelten RIVA und die Flußbeschleunigung nach Verapamilgabe deuten auf das Vorhandensein vasokonstriktorischer Mechanismen im gesamten Koronarsystem hin, die jedoch geringer ausgeprägt zu sein scheinen als im behandelten Gefäß.AbstractWe report on a 46-year-old male with unstable angina pectoris due to a total proximal occlusion of the left circumflex artery. At the side of a plaque rupture there was a thrombotic occlusion. With PTCA recanalization was possible, but a dissection occurred, therefore coronary stents were implanted. Besides an optimal morphological result and recurrent applications of nitroglycerin, the baseline blood flow velocity declined from initial 16 cm/s to 11 cm/s after PTCA down to 8.4 cm/s after stent implantation. Because peak flow velocity remained almost unchanged, the low baseline velocity (“slow flow phenomenon”) did not lead to an impaired coronary flow velocity reserve (CFVR). Only after application of 1 mg verapamil, a sustained flow velocity on a higher baseline level was reached (17 cm/s), at the same time typical signs of ischemia in the ECG (ST-segment depressions) improved. Additionally, in the non-treated LAD there was an increase in coronary blood flow velocity from 10 cm/s up to 25 cm/s.The reduction in coronary blood flow velocity with increasing manipulations might be due to an impairment of the coronary microcirculation with increasing α-adrenergic vasoconstriction, a distribution of vasoactive agents and peripheral microembolizations. Only after administration of verapamil, a calcium channel blocker with non-specific anti-adrenergic effects, the slow flow was removed and ECG signs of ischemia improved.The blood flow velocity in the non-treated LAD was low at baseline and improved after verapamil. This phenomenon leads to the conclusion that mechanisms with vasoconstrictive effect are present in the whole coronary system, but these mechanisms are less pronounced in non-treated vessels.

Neue Entwicklungen der parameterorientierten röntgendensitometrischen Perfusionsanalyse im Rahmen von Herzkatheteruntersuchungen

ZusammenfassungDie röntgendensitometrische Analyse von digitalen Subtraktionsangiokardiogrammen erlaubt eine qualitative und quantitative Erfassung des Kontrastmitteldurchstroms durch das epikardiale, das kapilläre und das koronarvenöse Gefäßsystem. Aus den so gewonnenen Dichte-Zeit-Kurven (Densogrammen) können Parameter berechnet werden, welche eine Beurteilung der lokalen Myokardperfusion erlauben. Diese sehr zeit- und rechenintensiven Vorgänge erlaubten bisher nur eine Anwendung in wenigen Zentren und waren praktisch nicht in das Routinevorgehen im Rahmen von Herzkatheteruntersuchungen zu integrieren. Erst durch Verbesserung der Computerhardware (Prozessorgeschwindigkeit, Festplattenspeicher, Digitalisierkarten), insbesondere jedoch durch eine softwaregesteuerte Automatisierung des EKG-getriggerten Bilddigitalisiervorgangs mit deutlich verbesserter zeitlicher Auflösung, durch semiautomatische Meßfensterpositionierung inklusive Referenzmeßfensterpositionierung zur Erfassung von Hintergrunddichteschwankungen und durch qualitätskontrollierte Parameteranalyse der Densogramme ist eine routinemäßige Anwendung im Rahmen von Herzkatheteruntersuchungen möglich geworden. Tierexperimentelle Untersuchungen stellten eine enge Beziehung zwischen dem so gewonnenen Parameter „Anstiegszeit” der Densogramme und der mittels farbkodierter Mikrosphärentechnik bestimmten lokalen Myokardperfusion dar. Klinische Anwendungen dieser Technik konnten zeigen, daß die poststenotische myokardiale Perfusionreserve, definiert als Quotient aus der Anstiegszeit vor und während pharmakologisch (Papaverin) induzierter Hyperämie, nach koronarer Ballonangioplastie und nach zusätzlicher Gefäßstützen-implantation verbessert wird, diese aber erst nach Gefäßstützenimplantation das intraindividuelle Referenzniveau, welches von einer nicht stenosierten Koronararterie versorgt wird, erreicht. Diese Ergebnisse verdeutlichen den zusätzlichen funktionellen Aspekt der koronaren Gefäßstützen-implantation auf die poststenotische Myokardperfusion zusätzlich zu dem morphologischen Aspekt der optimierten Gefäßlumenweitung.SummaryX-ray densitometric evaluation of digital subtraction coronary arteriograms allows a qualitative and quantitative detection of contrast medium propagation through the epicardial coronary arteries, the capillary system and the coronary venous system. So-called “time-density-curves” (TDCs) can be generated following Lambert-Beer’s law similar to indicator dilution curves by using contrast medium as the indicator. Several time and density parameters can be derived from these TDCs, which are related to local myocardial perfusion. Different animal validation studies have shown the applicability of this concept for in-vivo evaluation of coronary blood flow and myocardial perfusion. Nevertheless, absolute measurement of volumetric coronary blood flow or myocardial perfusion failed. Therefore, relative changes in coronary blood flow or myocardial perfusion in response to pharmacologically induced maximum hyperemia were measured and coronary or myocardial perfusion reserve was calculated as the ratio of hyperemic flow or perfusion devided by baseline values. Despite theoretical attractions for an application during routine cardiac catheterization, this densitometric approach did not get a wide acceptance. Primary reason for this limited use in specialized centers was the time consuming process of densitometric evaluation of the subtraction coronary arteriograms, which require digital cine angiography and necessitates enormous computer hard ware. This main limitation has been overcome since more powerful computer hard ware (processor speed, hard disk space, digitization boards) has become rapidly available during the last years at more moderate pricing and digital techniques today are state of the art in cardiac catheterization laboratories. In addition, soft ware program packages allowed an automatization of the digitization and densitometric evaluation process. These programs include ECG triggered cine image digitization with improved temporal resolution, semiautomatic definition of regions-of-interest including definition of reference regions-of-interest for the detection of background density changes and quality-controlled densitometric parameter analysis. This progress made an application during routine cardiac catheterization feasible.In animal validation studies this improved X-ray densitometric approach for evaluation of local myocardial perfusion was validated versus colour-coded microsphere techniques. The time parameter “rise time”, defined as the time from the start of local contrast medium induced density change to its maximum, revealed a close correlation (r2=0,965) to the results of the microsphere technique over a wide range of perfusion.We have applied this technique before and after coronary interventions such as balloon angioplasty and stenting. Results documented an improvement of poststenotic myocardial perfusion reserve immediately after coronary balloon angioplasty and an additional improvement after adjunct coronary stenting. Only after stenting but usually not after coronary balloon angioplasty alone poststenotic myocardial perfusion reserve gained the intraindividual reference level, measured in a perfusion bed supplied by an epicardial coronary artery without stenoses. These results documented the functional benefit of coronary stenting on poststenotic myocardial perfusion in addition to the well known morphologic benefit with the creation of a larger and more circular conduit.