Krishna Kandarpa

Risks and benefits of femoropopliteal percutaneous balloon angioplasty

PURPOSE The purpose of this study was to evaluate the efficacy of angioplasty in the treatment of femoropopliteal arterial disease. METHODS From 1980 to 1991, 126 angioplasty procedures were performed in 131 limbs of 106 patients with 175 femoropopliteal lesions (26 common femoral, 118 superficial femoral, and 31 popliteal). Critical ischemia was present in 55 limbs (42%), and claudication was present in 76 (58%). Angioplasty was performed for a single lesion in 87 limbs (66%) and for multiple lesions in 44 (34%). In 13 limbs (10%) the most severe lesion was an occlusion; in 118 (90%) all lesions were stenoses. Distal runoff was good (2 or 3 vessels patent) in 72 limbs (55%) and poor (0 or 1 vessel patent) in 59 (45%). RESULTS Death within 30 days occurred in 0.8%, nonfatal systemic morbidity in 7.1%, and local morbidity in 1.6% of procedures. Multivariate analysis revealed that indication and age were predictive of increased morbidity and mortality rates. Immediate success was achieved in 95% of limbs treated. Mean follow-up time was 2.0 years. The overall 5-year cumulative primary patency rate was 45% (+/- 5%). In a proportional hazards model indication and lesion type were predictive (p < 0.01) of long-term failure, with relative risks of 2.0 (1.2 to 3.3) and 2.7 (1.3 to 5.6), respectively. The 5-year primary patency rate after angioplasty for stenoses and claudication was 55% (+/- 7%), for stenoses and critical ischemia it was 29% (+/- 11%), and for occlusions it was 36% (+/- 14%). CONCLUSION These results suggest that femoropopliteal angioplasty is a low-risk procedure with acceptable long-term results in patients with claudication and stenoses.

Prototype miniature endoluminal MR imaging catheter.

PURPOSE The feasibility of a miniature endoluminal magnetic resonance (MR) detection coil was investigated for imaging mural and perimural anatomy of small, tubular structures. MATERIALS AND METHODS To this end, remotely tunable, single-loop, multiturn, receive-only radio-frequency coils, housed in 6-9-F arterial sheaths, were built. A 1.9-T imager was used. Phantom excitation was accomplished with a 62-mm-diameter bird-cage quadrature coil, and ex vivo specimen excitation was accomplished with a single-turn, untuned wire loop. Phantom images obtained with use of a 9-F catheter coil showed a signal-to-noise improvement on the border of 20 dB compared with images obtained with the quadrature coil. An 8-F catheter coil was used to obtain high-resolution (100 microns in-plane pixel size, 500 microns section thickness) spin-echo images (repetition time = 2,400 msec, echo time = 53 msec) of the wall of a fresh ex vivo human popliteal artery. RESULTS Prospectively, these images were suggestive of the presence of diffuse intimal hyperplasia, medial calcification, and focal atherosclerotic plaque. These findings were confirmed histologically. Three-dimensional restacking of the axial images simplified examination of the normal layers and pathologic changes within the wall. The improved signal-to-noise characteristics of these miniature coils permit fast high-resolution imaging, allowing visualization of microscopic anatomic details. CONCLUSIONS With further development, this technology may be useful for studying atherosclerosis and for providing imaging guidance during endoluminal MR interventions.

Assessment of peripheral intraarterial thrombolysis versus surgical revascularization in acute lower-limb ischemia: a review of limb-salvage and mortality statistics.

PURPOSE To review the risks and benefits of using peripheral intraarterial thrombolysis (PIAT) versus surgical revascularization (SR) as the initial treatment of acute lower-limb ischemia (ALLI). MATERIALS AND METHODS Two prospective, randomized trials that compared PIAT with SR in the treatment of ALLI were analyzed along with recent large, retrospective studies. Overall, 1,051 SR cases and 895 PIAT cases were included; when possible, the ischemic events were further categorized as acute, chronic, embolic, or thrombotic. Limb salvage and mortality at 30-day and 6-12-month follow-up were assessed. Combined percentages were derived by proportionally weighing each study. RESULTS When all studies were combined, limb salvage rates were 93% for PIAT and 85.5% for SR at 30 days and 89% versus 73%, respectively, at 6-12-month follow-up. Mortalities were 4% versus 15%, respectively, at 30 days and 8% versus 29%, respectively, at 6-12-month follow-up. CONCLUSION PIAT is associated with a substantially better limb-salvage rate and mortality than SR in the treatment of ALLI.

Safety of thrombolytic therapy with urokinase or recombinant tissue plasminogen activator for peripheral arterial occlusion: a comprehensive compilation of published work.

Purpose: To report a comprehensive literature review focused on comparing the risk of complications with urokinase versus recombinant tissue plasminogen activator (rtPA) for thrombolytic treatment of peripheral arterial occlusions. Methods: The English-language literature between 1985 and 2002 was searched for studies that used tissue-derived urokinase or rtPA in the treatment of peripheral arterial occlusions. Forty-eight studies (22 urokinase, 22 rtPA, and 4 that included both treatments) were identified, encompassing 2226 urokinase-treated patients and 1927 rtPA-treated patients. The safety of each thrombolytic agent was assessed based on the incidence of major hemorrhage, intracerebral hemorrhage, major limb amputation, transfusions, and mortality. Results: The review revealed a wide range of study protocols, patient conditions, ages of occlusions, dosages/delivery methods of lytic agents, and criteria for reporting complications. The incidence of major hemorrhage varied widely, but the overall rate was lower among urokinase-treated patients (6.2%) than for patients treated with rtPA (8.4%, p=0.007). The overall incidence of intracerebral hemorrhage was also significantly lower for urokinase (0.4% versus 1.1% for rtPA, p=0.020). The major amputation rate was similar for both treatments (urokinase 7.9%, rtPA 7.2%), but the mortality rate was significantly lower for urokinase (3.0% versus 5.6% for rtPA, p<0.001). The need for transfusions was less frequent with urokinase (11.1% versus 16.1%, p=0.002). Conclusions: These results from a large body of published literature suggest that urokinase may be associated with a lower incidence of complications than rtPA in the treatment of peripheral arterial occlusions.

A case of neurofibromatosis associated with a coronary artery aneurysm and myocardial infarction

A case of myocardial infarction secondary to thrombosis of a coronary artery aneurysm in a patient with neurofibromatosis is presented. The vascular manifestations of neurofibromatosis, and the associated clinical sequelae, are reviewed.

Dropped gallstones and surgical clips after cholecystectomy: CT assessment.

Aim: To describe the spectrum of computed tomographic (CT) findings in patients with dropped gallstones or dropped surgical clips after cholecystectomy. Materials and Methods: Seventeen patients diagnosed with dropped gallstones and 26 patients with dropped surgical clips on computed tomography after cholecystectomies were included in this study. The CT scans were evaluated for the number, location, size, and density of dropped gallstones or surgical clips and for the presence of an abscess. The cases were evaluated for the outcome on clinical and/or CT follow-up. Results: The location for dropped gallstones and dropped surgical clips after cholecystectomy was the Morrisons pouch in 17 and 12 patients, respectively. There were 9 abscesses in the study, all located in the Morrisons pouch. Duration from surgery to observation of abscess on computed tomography ranged from 5 days to more than 4.7 years. None of the patients with a dropped surgical clip from cholecystectomy developed an associated abscess. Conclusions: Subhepatic location was the most common location for dropped gallstones with associated abscess and for dropped surgical clips. Dropped cholecystectomy clips are not associated with increased risk of abscess formation and therefore do not need screening follow-up or operative removal. Abscess formation around dropped gallstone is a more common complication and requires surgical treatment in most when associated with an abscess.

Hemodynamic Evaluation of Arterial Stenoses by Computer Simulation

A new method to assess the hemodynamic severity of arterial stenoses was proposed and evaluated. It is based on a previously developed finite element computer simulation model for laminar-separated flow in arteries of axially varying cross-section; the present modification allows use of angiographic stenosis shapes acquired by automatic edge-detection algorithms. The method was validated by comparing its results with published experimental and theoretic results for ideal stenosis shapes. At moderate flowrates (Reynolds number = 500), poststenosis flow separation was predicted for moderately severe (75% area reduction) but not for mild (25%) stenoses. For high flowrates (Reynolds number = 900) in a severe stenosis (89%), stagnation and reversed flow were predicted and the experimental nondimensional pressure drop of 48.5 was correctly determined. Bernoullis Equation, which neglects viscosity, predicted a drop of only 40. For a severe stenosis (89%), even at low Reynolds numbers (50), reversed flow agreeing with other theoretic solutions was predicted. Predictions are especially useful at low flow rates, where experiments are difficult to conduct. The height of the curve on the graph of nondimensional pressure gradient vs. Reynolds number reflects the hemodynamic severity of a particular stenosis; these curves were predicted for moderate and severe ideal stenoses and agree with experiments. A similar analysis is applied to an actual human coronary artery stenosis, and the results are demonstrated to have use in assessing interventions during angiography.

Prospective Double-Blinded Comparison of MR Imaging and Aortography in the Preoperative Evaluation of Abdominal Aortic Aneurysms

The authors conducted a prospective double-blind study comparing spin-echo axial and coronal magnetic resonance (MR) imaging with aortography in the preoperative evaluation of 20 patients with abdominal aortic aneurysms. Receiver-operating-characteristic (ROC) analysis was used to evaluate the performance of MR imaging versus aortography in assessing arterial stenotic disease. Both modalities were equivalent in demonstrating the upper extent of the abdominal aortic aneurysms with respect to the renal and visceral arteries. MR imaging was superior in demonstrating aneurysmal iliac arteries and intraluminal thrombus. Although aberrant venous anatomy, associated pathologic changes, and other concomitant lesions were demonstrated with MR imaging, it performed poorly in assessing arterial stenoses and occlusions. Thus, the authors caution against the routine substitution of spin-echo MR imaging for aortography in the evaluation of abdominal aortic aneurysms. Conventional angiography should continue to be performed in patients with suspected mesenteric ischemia, significant hypertension, and symptomatic iliofemoral atherosclerosis, at least until robust MR angiographic techniques have proved themselves under similar rigorous clinical evaluation.

MDCT of 220 consecutive patients with suspected acute pulmonary embolism: incidence of pulmonary embolism and of other acute or non-acute thoracic findings

Purpose . This study was undertaken to evaluate the incidence of pulmonary embolism (PE) and other clinically relevant thoracic findings discovered on contrast-enhanced multidetector computed tomography (MDCT) examination in patients with a suspicion of acute PEMaterials and methods . We retrospectively reviewed 220 reports of 40-row MDCT exams in consecutive patients (101 men, 119 women; mean age 55 years±18) suspected for acute PE. Presenting symptoms and risk factors were recorded. Image quality and incidence of PE and other clinically relevant thoracic findings were evaluatedResults . MDCT were diagnostic in 96.8% of patients. Nineteen patients (8.6%) were positive for PE. Signs and symptoms were present in 82.7% (182) and risk factors in 38.2% (84) of the population. Clinically relevant thoracic findings were detected in 45.9% (101) of the patients. Ten patients had PE and other thoracic findings. Half of the patients (110) had neither PE nor other clinically relevant thoracic findingsConclusions . Chest MDCT, with an excellent overall image quality, provided an explanation for the clinical presentation in about 50% of emergency department patients studied and was useful in detecting PE and other thoracic diseases with symptoms mimicking PE. However, half of the exams were negativeRiassuntoObiettivo . Scopo dello studio è valutare l’incidenza di embolia polmonare (EP) e di altri reperti toracici clinicamente rilevanti, in esami di tomografia computerizzata multi-detettore (TCMD) con mezzo di contrasto, in pazienti con sospetta embolia polmonare acutaMateriali e metodi . Abbiamo analizzato retrospettivamente i referti TC 40-strati di 220 pazienti consecutivi (101 maschi, 119 femmine; età media 55±18 anni) con sospetto di EP acuta. Sono stati raccolti sintomi e fattori di rischio. Abbiamo valutato la qualità delle immagini e l’incidenza di EP e di altri reperti toracici clinicamente rilevanti. Risultati. La TCMD è risultata diagnostica nel 96,8% dei pazienti. L’82,7% (n=182) dei pazienti aveva segni/sintomi, il 38,2% (n=84) fattori di rischio. All’8,6% dei pazienti (n=19) è stata fatta diagnosi di embolia polmonare, al 45,9% (n=101) sono stati identificati altri reperti toracici clinicamente rilevanti. Dieci pazienti avevano sia EP sia altri reperti toracici. Metà della popolazione (n=110) non aveva né EP né altri reperti toracici clinicamente rilevantiRisultati . La TCMD è risultata diagnostica nel 96,8% dei pazienti. L’82,7% (n=182) dei pazienti aveva segni/sintomi, il 38,2% (n=84) fattori di rischio. All’8,6% dei pazienti (n=19) è stata fatta diagnosi di embolia polmonare, al 45,9% (n=101) sono stati identificati altri reperti toracici clinicamente rilevanti. Dieci pazienti avevano sia EP sia altri reperti toracici. Metà della popolazione (n=110) non aveva né EP né altri reperti toracici clinicamente rilevantiConclusioni . La 40-TCMD del torace, grazie anche ad un’eccellente qualità dell’immagine, ha fornito una spiegazione alla presentazione clinica in circa metà dei pazienti studiati, risultando utile nell’identificazione dell’embolia polmonare e di altre patologie toraciche con sintomi simili. Tuttavia la metà degli esami è risultata negativa

Technical Determinants of Success in Catheter-directed Thrombolysis for Peripheral Arterial Occlusions

Local intraarterial thrombolytic therapy restores blood flow to the ischemic limb by dissolving the occlusive thrombus and identifies culprit lesions for treatment by means of surgical and/or percutaneous procedures. The techniques used for administration of the thrombolytic agent, the drug used, and the criteria for termination of the therapy are all factors that can influence both technical success and speed of lysis. This article discusses these factors and their influence on thrombolytic success.