Percutaneous aspiration thromboembolectomy to manage the embolic complications of angioplasty and as an adjunct to thrombolysis

Percutaneous aspiration thromboembolectomy (PAT) can be used to treat the embolic complications of angioplasty. The same technique is of value during thrombolysis to remove large pieces of thrombus. We report on our experience with PAT in 21 patients. Fourteen of these patients had embolization complicating peripheral angioplasty and in one case embolus complicated directional atherectomy. PAT was successful in 87% of these patients (13/15). In six patients undergoing thrombolysis of acute peripheral occlusions, all had successful PAT to shorten their treatment episode immediately prior to angioplasty of any underlying stenosis. PAT can be performed with a simple, inexpensive catheter under fluoroscopic control and therefore offers significant advantages over a surgical embolectomy using the Fogarty balloon catheter. PAT is a useful treatment option for the vascular radiologist.

Perforations after percutaneous coronary interventions: clinical, angiographic, and therapeutic observations

Coronary perforation is a rare, but potentially catastrophic, complication of percutaneous coronary intervention. A retrospective review of the Cardiology Quality Assurance Database was performed for all percutaneous coronary interventions (n = 8,932) at William Beaumont Hospital from October 1988 to December 1992. Coronary artery perforation was reported in 35 patients (0.4%), including after percutaneous transluminal coronary angioplasty (PTCA, 11/7,905, 0.14%), transluminal extraction coronary atherectomy (TEC, 6/420, 1.3%), directional coronary atherectomy (DCA, 1/249, 0.25%), and excimer laser coronary angioplasty (ELCA, 5/242, 2%); and none after high-speed mechanical rotational atherectomy with the Rotablator (MRA, 0/116, 0%). Perforations were classified by coronary angiography as free perforations (n = 10), contained perforations (n = 17), or other types of perforation (n = 8). Although perforation was apparent in 32 (91%) of 35 angiograms, delayed cardiac tamponade occurred in 3 patients (9%), despite the absence of angiographic evidence for perforation at the time of the procedure. Causes of perforation were the guidewire in 7 (20%), an interventional device in 26 (74%), and indeterminate in 2 (6%). Complex B2 or C lesions accounted for 83% of perforations. Final treatment included conservative therapy (reversal of anticoagulation and/or PTCA) in 22 (63%) and surgical intervention (with or without bypass surgery) in 13 (37%). Serious clinical complications included cardiac tamponade in 6 (17%), blood transfusion in 12 (34%), myocardial infarction in 9 (26%), and death in 3 (9%).

Scintigraphic localization of the bleeding site of a large retroperitoneal hematoma following renal angioplasty

Although the scintigraphic detection of a few soft tissue hematomas have been reported, these usually have been serendipitous discoveries that were small and self-limited. The authors report a case of a large, rapidly expanding retroperitoneal hematoma that occurred following a left renal angioplasty. While the hematoma was initially detected by CT imaging, the precise source of the bleeding could not be definitively localized. Scintigraphy with labeled RBC cells, however, identified the left femoral artery puncture site as the bleeding source, which was subsequently surgically repaired.

Electrophysiologic basis for T wave alternans as an index of vulnerability to ventricular fibrillation

Substantial evidence indicates that T wave alternans is an intrinsic property of ischemic myocardium. The electrophysiologic basis appears to be spatial and temporal heterogeneity of repolarization resulting from changes in action potential morphology rather than in activation sequence. Ischemia-induced changes in postrepolarization refractoriness and depressed electrical restitution of action potential duration have also been implicated. The main underlying ionic basis for T wave alternans during coronary occlusion appears to be derangements in intracellular cycling of calcium. Accumulation of potassium in the extracellular space adjoining ischemic cells and disruption in electrogenic sodium-calcium exchange may also be involved. In humans, T wave alternans has been observed in Prinzmetal's and classical angina, angioplasty, and bypass graft occlusion. Under these conditions associated with acute myocardial ischemia, alternans is restricted to the ischemic zone, and alternation in action potential morphology is an underlying factor. Recently, repolarization alternans has been shown to be a statistically significant predictor of the results of electrophysiologic testing and arrhythmia-free survival in individuals with and without organic heart disease. Collectively, these observations provide a rationale for quantitation of T wave alternans magnitude for assessment of vulnerability to life-threatening ventricular arrhythmias both in response to and independent of the effects of myocardial ischemia.

[Preventive percutaneous radiotherapy for avoiding hyperplasia of the intima following angioplasty together with stent implantation]

PURPOSE AND BACKGROUND

Interventional radiologic procedures play an important role in the management of peripheral arterial occlusive disease. Percutaneous transluminal interventions as angioplasty (PTA) and implantations of metal-stents injure the wall of the blood vessels resulting in hyperplasia of the intima and media. In spite of adequate anticoagulation therapy restenosis and reocclusion frequently occur. Our study was designed to prevent hyperplasia of the intima by percutaneous radiation therapy.

PATIENTS AND METHODS

A total of 24 patients had a stent implanted in their superficial femoral artery from 1990 to 1992. Eleven patients received percutaneous radiation therapy of the enlarged stent area on five consecutive days with a single dose of 2.5 Gy thus resulting in a total dose of 12.5 Gy. Both patients groups were compared. None of the patients in the radiation group suffered from complications.

RESULTS

In the seven months following stent implantation and radiation only two of eleven patients in the radiation group suffered from occlusion of the stent that had to be treated by vascular surgery. In comparison five of 13 patients treated with stent implantation alone suffered from occlusion of the stent within the first eight to nine months.

CONCLUSION

In spite of a small case number our study shows a positive influence of percutaneous radiation therapy on the extent of hyperplasia of the intima after stent implantation leading to lower reocclusion rates. Whether these results can be improved by alternative dose-fractionation schedules has to be addressed by further studies.

Long-term results of a single protocol for thrombolysis in acute lower-limb ischaemia

In a prospective study, 78 of 157 patients with acute lower-limb ischaemia were considered suitable for thrombolysis. The immediate and 4-year results of 52 patients managed by a single protocol are reported. Of 34 patients alive at 4 years, 23 had limb salvage. Initial treatment produced effective lysis in 38 patients (73 per cent) with significant benefit in 35 (67 per cent); that benefit was sustained for a minimum of 4 years in 30 patients (58 per cent). Seven of the 18 deaths by 4 years occurred within 30 days. Amputation was carried out in six patients within 30 days and in five during the next 4 years. Delayed amputation followed persistent distal occlusion or progression of distal disease. No death or amputation was caused by complication of treatment. In selected patients the risks of thrombolysis can be reduced to an acceptable level by personal supervision and a strict protocol. In survivors, limb salvage is generally sustained for at least 4 years.

Potentiation of the vasospastic response to angioplasty by pretreatment with fluoxetine. A study in the atherosclerotic rabbit

There is evidence that angioplasty-induced vasospasm is mediated by serotonin (5-hydroxytryptamine [5-HT]) release from platelets. We tested the hypothesis that pretreatment of the atherosclerotic rabbit with fluoxetine, a platelet-uptake inhibitor of 5-HT, would reduce vasospasm after balloon angioplasty. Short-term administration of fluoxetine reduced platelet 5-HT uptake to 4% of baseline. Daily administration of fluoxetine for 7 days reduced whole-blood 5-HT levels to 28% of baseline. Thus, fluoxetine inhibited platelet 5-HT uptake in this model as predicted. Contrary to our expectations and despite the substantial reduction in whole-blood 5-HT levels, pretreatment with fluoxetine for 1 week resulted in augmentation of angioplasty-induced vasospasm in atherosclerotic rabbits. Intraperitoneal administration of fluoxetine produced vasoconstriction in normal rabbits that was augmented by 5-HT and not reversed with LY53857, a specific serotonin receptor antagonist. We postulate that this new observation is probably a result of the inhibition of the clearance mechanism for serotonin, with resultant enhancement of the effect of serotonin released by the activated platelets that are deposited on the vessel wall surface at the time of angioplasty. A direct effect of fluoxetine on serotonergic receptors is a second possible mechanism for the observed effect.

Does peripheral angioplasty compromise limb blood flow?

Isotope limb blood flow studies were carried out using balloon, laser and Kensey catheter techniques to assess the outcome of peripheral angioplasty. Limb blood flow and Doppler ankle-brachial pressure measurements were obtained before angioplasty and at 6 months after angioplasty in a total of 101 angioplastied limbs: A fall in limb blood flow at 6 months was seen in 17% of the angioplastied limbs with no significant difference in the figures for the different types of angioplasty. Limb blood flow was also measured in 53 contralateral untreated limbs, approximately half of the patient group having both legs angioplastied. 25% of untreated limbs showed a fall in limb blood flow. Significantly more of the untreated limbs showed a fall in limb blood flow at 6 months where the contralateral, treated limb did not improve as a result of the angioplasty compared with those patients where the angioplastied leg improved. These results suggest that a lack of improvement in blood flow in the angioplastied limb may not result from failure of the angioplasty but may be the result of some factor, or combination of factors, which adversely affects both the angioplastied and the untreated leg in some patients.

Inhibition of smooth muscle cell proliferation and experimental angioplasty restenosis by beta-cyclodextrin tetradecasulfate

Heparin inhibits smooth muscle cell proliferation in vitro, a property that makes it potentially useful in preventing restenosis after angioplasty. Its utility in this setting is limited by the inability to use high doses (secondary to anticoagulant effects) and the need for subcutaneous administration. We tested the ability of beta-cyclodextrin tetradecasulfate (CDT), a nonanticoagulant synthetic heparin mimic, to inhibit smooth muscle cell proliferation in vitro and tested its efficacy when orally administered for the prevention of angioplasty restenosis in a rabbit atherosclerosis model. Vascular smooth muscle cells were cultured from rabbit aortas by the explant technique. Passaged cells were plated at low density in microtiter plates in the presence or absence of varying concentrations of heparin or CDT in culture medium containing 10% fetal calf serum. Using both 3H-thymidine incorporation and total protein assays, both heparin and CDT caused a similar dose-dependent inhibition of proliferation. We next tested the effect of orally administered CDT in the prevention of restenosis in focal femoral artery arteriosclerotic lesions created in hypercholesterolemic New Zealand White rabbits by air-dessication endothelial injury and subsequent peripheral angioplasty. Animals were followed up for 1 month and were fed normal chow supplemented by tap water with or without CDT. In animals receiving the highest concentration of CDT (2 mg/mL drinking water), the percentage of arterial cross-sectional area with intimal hyperplasia decreased from 50.5 +/- 1.7% (control) to 26.9 +/- 2.2% (p < 0.001), with the intimal/medial ratio being decreased from 1.4 +/- 0.4 to 0.5 +/- 0.2 (p = 0.056).(ABSTRACT TRUNCATED AT 250 WORDS)

Recanalization of chronic arterial occlusions: low-speed rotational angioplasty. 5 years experience in peripheral and coronary vessels

Chronic complete occlusions still represent the major technical limitation of percutaneous transluminal angioplasty, both in peripheral and coronary vessels. The clinical use of low-speed rotational angioplasty started in 1986 for the peripheral and in 1987 for the coronary arteries, and has already become part of the clinical routine in several centres. Up to now more than 350 patients with peripheral and 250 patients with coronary occlusions have been treated in Frankfurt; a multicentre questionnaire already contains information about 1,252 patients with peripheral vessel obstructions. In peripheral occlusions the acute success rate was more than 80% if low speed rotational angioplasty was used as the first attempt; after failure of conventional techniques still more than 60% of the vessels could be recanalized successfully. In addition to occlusions of the arteries of the lower limb, indications now may include the iliac artery and the subclavian artery. In each of the patients with chronic coronary occlusions an attempt with conventional techniques had failed before. Following a learning curve, which was also influenced by a better understanding of morphological preconditions, the acute success has now reached 70%. Both in patients with peripheral and those with coronary occlusions the technique turned out to be a safe procedure. Early angiographically documented long-term results in both indications are comparable with conventional balloon techniques. It is concluded that the use of low-speed rotational angioplasty (ROTACS) can improve the results of non-operative invasive treatment, both in peripheral and in coronary arteries.

Update on PTCA: what are its limitations? Can they be overcome by new devices? A look at atherectomy, intra-arterial stents, and laser catheters

Complications limiting the use of percutaneous transluminal coronary angioplasty (PTCA) include abrupt vessel closure and restenosis. Certain coronary lesions, such as chronic total occlusions and diffuse or long stenoses, pose serious technical difficulties. New devices may overcome some of these limitations. For example, atherectomy may prove useful for thrombotic vessels or diffusely diseased vein grafts, and it may lower restenosis rates in larger vessels. Stents are currently used as a bailout measure when acute dissection occurs. Although lasers produce smoother margins than does conventional PTCA and effectively ablate atherosclerotic plaque material, the restenosis rate associated with use of these devices may be similar to that of conventional PTCA.

Percutaneous coronary intervention for diffuse coronary artery disease

Patients with diffuse coronary artery disease present a significant management problem. It has been proposed that diffuse coronary disease is unsuitable for balloon angioplasty and surgical treatment is not ideal either. We review the evidence that coronary balloon angioplasty is not a suitable treatment for diffuse coronary disease and examine the role of alternative interventional techniques. New techniques including long angioplasty balloon catheters and atherectomy devices have shown promise. If this is confirmed by prospective randomized trials then coronary angioplasty may yet prove an attractive treatment for diffuse coronary disease.

The use of risk-adjusted complication rates to compare hospitals performing coronary artery bypass surgery or angioplasty

A hospital's quality of care is generally assessed by a review of individual records. This study used unadjusted and risk-adjusted complication rates to measure the quality of care for hospitals that perform coronary artery bypass surgery or angioplasty. Hospitals differed greatly in their complication rates. Only a small percentage of this difference was due to differences in the risks that patients faced.

Intravascular ultrasound assessment of arterial dissection, intimal flaps, and intraarterial thrombi

Arterial dissection, intimal tears, and intraluminal thrombosis are common sequelae of catheter-based interventional procedures for coronary artery disease. These may not be recognized reliably by contrast angiography. Intravascular ultrasound imaging is an innovative method that allows visualization of the cross-sectional anatomy with high-resolution real-time images. This article presents the recent experience in arterial imaging with this method. Studies documenting the ability of intravascular ultrasound to demonstrate arterial atherosclerosis and to unmask some problems related to atherosclerotic disease and its treatment by catheter-based maneuvers are presented. Problems of arterial dissection, intimal flaps, and intravascular thrombosis are described with in vitro and in vivo documentation of the capability of intravascular ultrasound to visualize these abnormalities. The clinical implications of real-time imaging of intimal flaps and intraluminal clots, and the possible value of this imaging modality in the performance of catheter-based therapeutic procedures for coronary and peripheral arterial disorders are discussed.