Peter Probst

Prognostic value of intracoronary flow velocity and diameter stenosis in assessing the short- and long-term outcomes of coronary balloon angioplasty - The DEBATE study (Doppler Endpoints Balloon Angioplasty Trial Europe)

BACKGROUND The aim of this prospective, multicenter study was the identification of Doppler flow velocity measurements predictive of clinical outcome of patients undergoing single-vessel balloon angioplasty with no previous Q-wave myocardial infarction. METHODS AND RESULTS In 297 patients, a Doppler guidewire was used to measure basal and maximal hyperemic flow velocities proximal and distal to the stenosis before and after angioplasty. In 225 patients with an angiographically successful percutaneous transluminal coronary angioplasty (PTCA), postprocedural distal coronary flow reserve (CFR) and percent diameter stenosis (DS%) were correlated with symptoms and/or ischemia at 1 and 6 months, with the need for target lesion revascularization, and with angiographic restenosis (defined as DS > or = 50% at follow-up). Logistic regression and receiver operator characteristic curve analyses were applied to determine the prognostic cutoff value of CFR and DS separately and in combination. Optimal cutoff criteria for predictors of these clinical events were DS, 35%; CFR, 2.5. A distal CFR after angioplasty > 2.5 with a residual DS < or = 35% identified lesions with a low incidence of recurrence of symptoms at 1 month (10% versus 19%, P=.149) and at 6 months (23% versus 47%, P=.005), a low need for reintervention (16% versus 34%, P=.024), and a low restenosis rate (16% versus 41%, P=.002) compared with patients who did not meet these criteria. CONCLUSIONS Measurements of distal CFR after PTCA, in combination with DS%, have a predictive value, albeit modest for the short- and long-term outcomes after PTCA, and thus may be used to identify patients who will or will not benefit from additional therapy such as stent implantation.

Coronary-artery stenting compared with balloon angioplasty for restenosis after initial balloon angioplasty. Restenosis Stent Study Group.

BACKGROUND Intracoronary stenting reduces the rate of restenosis after angioplasty in patients with new coronary lesions. We conducted a prospective, randomized, multicenter study to determine whether intracoronary stenting, as compared with standard balloon angioplasty, reduces the recurrence of luminal narrowing in restenotic lesions. METHODS A total of 383 patients who had undergone at least one balloon angioplasty and who had clinical and angiographic evidence of restenosis after the procedure were randomly assigned to undergo standard balloon angioplasty (192 patients) or intracoronary stenting with a Palmaz-Schatz stent (191 patients). The primary end point was angiographic evidence of restenosis (defined as stenosis of more than 50 percent of the luminal diameter) at six months. The secondary end points were death, Q-wave myocardial infarction, bypass surgery, and revascularization of the target vessel. RESULTS The rate of restenosis was significantly higher in the angioplasty group than in the stent group (32 percent as compared with 18 percent, P= 0.03). Revascularization of the target vessel at six months was required in 27 percent of the angioplasty group but in only 10 percent of the stent group (P=0.001). This difference resulted from a smaller mean (+/-SD) minimal luminal diameter in the angioplasty group (1.85+/-0.56 mm) than in the stent group (2.04+/-0.66 mm), with a mean difference of 0.19 mm (P=0.01) at follow-up. Subacute thrombosis occurred in 0.6 percent of the angioplasty group and in 3.9 percent of the stent group. The rate of event-free survival at 250 days was 72 percent in the angioplasty group and 84 percent in the stent group (P=0.04). CONCLUSIONS Elective coronary stenting was effective in the treatment of restenosis after balloon angioplasty. Stenting resulted in a lower rate of recurrent stenosis despite a higher incidence of subacute thrombosis.

Relation of coronary arterial occlusion pressure during percutaneous transluminal coronary angioplasty to presence of collaterals

To investigate the relation of the gradient across a coronary artery stenosis and the pressure distal to the stenosis after proximal occlusion during percutaneous transluminal coronary angioplasty to the amount of angiographically estimated collateral circulation, 63 patients (55 men, 8 women) were studied. All patients had 1-vessel disease (54 left anterior descending, 8 right coronary artery and 1 circumflex coronary artery). All patients had documented ischemia, and angioplasty was carried out within 4 weeks after the initial angiogram. The patients were separated into 4 groups: 0 = no collaterals (35 patients), +1 = just visible collaterals (8 patients), +2 = collaterals without reaching the contralateral vessel (10 patients), and +3 = filling of the contralateral vessel (10 patients). There was no difference in age among the 4 groups. There was a significant negative relation of the gradient vs the extent of collateral circulation, although the degree of stenosis increased significantly from group 0 to group +3. There was a significant positive relation of the occlusion pressure (in absolute terms and in percent of the proximal systolic pressure) vs the extent of collateral circulation. There was a significantly smaller change of the occlusion pressure vs the distal pressure before occlusion if good collaterals were present. The occlusion pressure remained constant during 1 occlusion up to 40 seconds and was reproducible in 3 successive occlusions. In conclusion, the pressure distal to a coronary artery stenosis is mainly dependent on the severity of the stenosis and on the collateral flow. If anterograde flow is eliminated by proximal occlusion the distal pressure is only dependent on the extent of collateral circulation.

Use of a Collagen Plug Versus Manual Compression for Sealing Arterial Puncture Site After Cardiac Catheterization

The aim of the study was to investigate (1) the safety and efficacy of the application of a collagen plug (Vasoseal®) at arterial puncture sites, (2) the hemostasis time, and (3) the comfort for the patient of a collagen plug (Vasoseal®) when compared with manual compression. Sixty-two patients were randomized either for application of a collagen plug (Vasoseal®, group A, n=33) or manual compression (group B, n=29) after cardiac catheterization. All patients were evaluated for subjective pain score ranging from 1 to 5 (1= no pain up to 5 =very strong pain). In addition the authors measured the time until hemostasis could be achieved. The patients were evaluated by duplex sonography for complications at days 1 and 7 after the procedure. The pain score demonstrated a signif icantly lower score in group A when compared with group B (P=0.01). The mean time for hemostasis was significantly lower in group A (mean 9.6 minutes) when compared with group B (mean 23.6 minutes) (P=0.0001). Regarding the complication rate there was no significant difference between the groups (group A vs group B, P=0.82). The authors conclude that the application of a collagen plug at the arterial puncture site is a safe and time-saving method. In addition it is less painful and therefore better tolerated than manual compression.

Estimation of coronary flow reserve by transesophageal coronary sinus Doppler measurements in patients with syndrome X and patients with significant left coronary artery disease

OBJECTIVES This study sought to determine the feasibility of coronary sinus flow velocity analysis by transesophageal Doppler echocardiography for estimation of coronary flow reserve in patients with syndrome X and patients with coronary artery disease. BACKGROUND Coronary flow reserve provides useful information in patients with coronary artery disease and patients with syndrome X. Current methods of measuring coronary flow reserve are invasive or require extensive laboratory equipment, or both. Transesophageal Doppler recordings of coronary sinus flow velocity before and after vasodilator application may allow noninvasive determination of coronary flow reserve. METHODS We obtained coronary sinus flow velocity recordings before and after dipyridamole administration (0.6 mg/kg body weight per 5 min) in 9 patients with syndrome X, 14 with significant left coronary artery disease and 22 age-matched control patients. We used the formula anterograde minus retrograde flow velocity time integral times heart rate as an index of coronary sinus flow. Coronary flow reserve was calculated by dividing coronary sinus flow variables after dipyridamole administration by the respective baseline values. RESULTS Technically adequate recordings were obtained in 44 (98%) of 45 patients. Compared with that in the control group (2.78 +/- 0.95 [mean +/- SD]), coronary flow reserve was significantly lower in patients with syndrome X (1.21 +/- 0.23, p < or = 0.001) as well as in those with coronary artery disease (1.47 +/- 0.7, p < or = 0.001). Using a cutoff coronary flow reserve value of 1.8, sensitivity, specificity and overall predictive value of coronary flow reserve determinations were, respectively, 100%, 91% and 94% for syndrome X and 86%, 91% and 89% for coronary artery disease. CONCLUSIONS Coronary flow reserve calculation by transesophageal coronary sinus flow velocity recordings is feasible in a large proportion of patients and might be useful for the noninvasive evaluation of patients with syndrome X and patients with severe left coronary artery disease.

Assessment of coronary stenoses by Doppler wires: a validation study using in vitro modeling and computer simulations

The present study evaluates the use of intracoronary velocity measurements by Doppler guidewires for assessing coronary obstructions. In vitro experiments were performed in a flow model using acrylic phantoms of coronary stenoses with different configurations (stenosis area: 56%, 75% and 89%; stenosis length: 1 and 5 mm; stenosis border: tapering or abrupt). Nonpulsatile laminar flow conditions of a test fluid were established at flow rates ranging from 0.5 to 2.0 mL/s to simulate baseline flow and flow after vasodilation. Peak Doppler velocity was measured proximal to, within and distal to the model stenoses. Computer simulations were employed to calculate radial flow profiles with and without a Doppler wire aligned with the vessel center. In 84 in vitro flow experiments, peak Doppler velocity correlated well with the average flow velocity as calculated from the actual flow rate and the vessels cross-sectional area proximal to (r = 0.98, SEE = 1.4, p < 0.001) and within (r = 0.97, SEE = 16.4, p < 0.001) the stenosis. However, the ratio of calculated average velocity to Doppler-measured peak velocity was significantly different from 0.5, the expected value for a parabolic flow profile (0.76+/-0.08, 0.81+/-0.14; p < 0.001). Acceptable accuracy was found for the Doppler estimation of stenosis severity using the continuity equation (error: 0.9+/-1.2% and -4.6+/-3.5% for stenosis with a length of 5 mm and 1 mm, respectively). Doppler velocity reserve significantly underestimated the true flow reserve for the 56% and 75% stenoses (p < 0.01). Computer simulations demonstrated significant alterations of flow profiles by the wire, which explained the observed underestimation of the true flow reserve by the Doppler velocity reserve. Thus, Doppler guidewire measurements of intracoronary flow velocities are useful to assess the severity of coronary stenoses. However, the in vitro results and computer simulations indicate that guidewires alter the flow profile, so that Doppler velocity reserve may underestimate the true flow reserve.

The HQ time in congestive cardiomyopathies

Abstract 1. 1. In 41 per cent of patients with COCM there was a bundle branch block. All but one of these 18 patients showed a prolonged HQ time, indicating that the whole conduction system in these cases is involved and that there is just a predominance of one side. 2. 2. Fifty-nine per cent had a normal QRS complex and 50 per cent of these patients showed a prolonged HQ time. It must be assumed that in these cases the whole conduction system is diffusely involved to the same degree. This results in a pure HQ prolongation and not in bundle branch block. 3. 3. Patients with ICM showed significantly less often an HQ prolongation, indicating that the conduction system in these cases is not diffusely involved. 4. 4. The significant negative correlation between HQ time and EF indicates that the progression of the myocardial disease is concomitant with the progression of the conduction disturbances, which can be either diffuse in both branches, leading to a pure HQ prolongation, or be predominant in one of the bundles, leading to a bundle branch block with an HQ prolongation. 5. 5. There are no significant differences of the end-diastolic volumes within the group of COCM and between patients with COCM and ICM. Thus, ventricular enlargement, and myocardial dilatation, respectively, are not the cause of HQ prolongation.

Assessment of left ventricular function: comparison between radionuclide angiography and semiquantitative two-dimensional echocardiographic analysis

Measurement of global left ventricular function is important in the follow-up of cardiac patients and is a good prognostic indicator in acute cardiac situations. We compared quantitative measurements of global left ventricular function made with radionuclide angiography (RNA) and contrast cardiac ventriculography (CVG) to visual semiquantitative estimates from two-dimensional echocardiographic images (2D-echo). Three hundred and thirty-nine consecutive patients who underwent RNA were assessed with 2D-echo within 3 months. In addition, 92 of these patients also underwent CVG (correlation of ejection fraction between CVG and RNA:r=0.82;P<0.0001). The RNA mean ejection fractions in the four 2D-echo groups (0=normal, 1=slightly, 2=moderate, or 3=severe reduced left ventricular function) differed markedly (P<0.0001); however, there was overlapping among the groups (2D-echo score/RNA ejection fraction: 0=57.3%±12.8%; 1=46.0%±12.9%; 2=29.6%±12.2%; and 3=24.6%±11.5%) and the difference between 2D-echo scores 2 and 3 was not significant. 2D-echo showed a good concordance in RNA classes (0=≥505; 1=35%–49%; 2=21%–34%; and 3=≤520% ejection fraction) 0 (133/166; 80%) and 3 (18/30; 60%) but low concordance in classes 1 (27/82; 33%) and 2 (21/61; 34%). For accurate assessment of global left ventricular ejection fraction, visual semiquantitative judgement of a 2D echocardiographic image is limited in comparison to CVG or RNA, especially in patients with a slight or moderate reduction in left ventricular ejection fraction.

Transesophageal versus intracoronary Doppler measurements for calculation of coronary flow reserve

OBJECTIVE The present study was performed to compare coronary flow reserve by transesophageal Doppler echocardiography and intracoronary Doppler flow wire measurements in patients with LAD disease. METHODS 17 patients with various degree of LAD stenosis were studied. Intracoronary LAD Doppler measurements were performed at baseline and after intracoronary injection of 18 micrograms adenosine. Transesophageal coronary sinus and LAD Doppler measurements were performed at baseline and after intravenous dipyridamole (0.6 mg/kg/5 min). Coronary flow reserve was calculated as the ratio of hyperemic to baseline average peak velocities. RESULTS Coronary flow reserve was 2.44 +/- 0.62 and 2.19 +/- 0.76 for proximal and distal intracoronary measurements and was 2.25 +/- 0.64 and 1.74 +/- 0.63 for transesophageal LAD- and coronary sinus measurements. Proximal intracoronary flow reserve significantly correlated with transesophageal coronary sinus (r = 0.73, p < or = 0.001) and LAD (r = 0.70, p < or = 0.005) measurements, whereas distal intracoronary flow reserve only correlated with transesophageal coronary sinus flow reserve (r = 0.56, p < or = 0.02). Receiver operating characteristic curve analysis demonstrated similar diagnostic accuracy of all applied techniques for detection of a significant LAD stenosis. CONCLUSIONS Coronary flow reserve by both transesophageal techniques correlated with intracoronary Doppler flow wire measurements, however considerable discrepancies may occur in the individual patient.

Heparin induced increase of t-PA antigen plasma levels in patients with unstable angina: No evidence for clinical benefit of heparinization during the initial phase of treatment

Patients with unstable coronary artery disease were randomly treated either with a combination therapy consisting of nitrates and calcium-channel blockers without or with addition of clinical grade heparin administered subcutaneously; in order to evaluate the effect of heparin treatment on the fibrinolytic system, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) plasma levels were related to the clinical course of the disease. In heparinized patients thrombin time was prolonged more than 3-fold the normal range indicating effective heparin treatment. Heparinization led to a significant increase in t-PA antigen plasma levels (p less than 0.0001) within approximately four hours while PAI-1 activities remained unaltered. However, the measurable increase of the anticoagulant and pro-fibrinolytic activities of heparin did not result in a short-term benefit for the heparinized patients because the number of further ischemic attacks per patient during the observation period of three days was not different between the two study groups.