Outcome after prolonged balloon inflations of greater than 20 minutes for initially unsuccessful percutaneous transluminal coronary angioplasty

Peripheral arterial balloon angioplasty: effect of short versus long balloon inflation times on the morphologic results

PURPOSE

To evaluate the effect of different balloon inflation times on angiographic results in peripheral angioplasty.

MATERIALS AND METHODS

Seventy-four infrainguinal arteriosclerotic lesions were randomized prospectively to undergo balloon dilation for 30 seconds (group I) or 180 seconds (group II). Each group consisted of 37 patients. Postinterventional angiograms were evaluated by two blinded readers. Dissections were graded as follows: 1 = no dissection; 2 = minor flap; 3 = extensive dissection membrane, not flow limiting; or 4 = flow-limiting flap. The rate of major-grade dissections (grades 3 and 4), residual stenosis (>30%), and further interventions were compared with the two-tailed chi(2) test.

RESULTS

In group I, major dissections were noted in 16 patients (43%) compared with five patients (14%) in group II (P =.009). Residual stenoses were found in 12 patients (32%) in group I compared with five patients (14%) in group II (P =.096). The rate of additional interventions was significantly higher in group I than in group II (20 of 37 vs nine of 37; P =.017).

CONCLUSION

A prolonged inflation time of 180 seconds improves the immediate angioplasty result of infrainguinal lesions compared to a short dilation strategy. Significantly fewer major dissections and a modest reduction of residual stenoses are observed. The requirement of costly and time-consuming further interventions is significantly reduced.

Temporary Strecker stent for management of acute dissection in popliteal and crural arteries

Stent placement is a widely used bail-out treatment for dissection of peripheral arteries. Below the level of the superficial femoral artery permanent stenting is complicated by a high incidence of subacute thrombosis and restenosis. We present two cases of arterial occlusion due to acute iatrogenic dissection of the popliteal and distal fibular arteries. Successful treatment was achieved with a new bail-out procedure. Strecker stents were implanted to seal off the dissection flap. Stents were retrieved easily after 24 hr using a myocardial biopsy forceps. After stent retrieval the temporarily stented segments were patent and showed a larger lumen compared with segments treated by balloon dilatation alone. Temporary stenting is a simple and safe procedure and offers the advantage of tacking up dissection membranes and preventing recoil. Persistent presence of a metallic implant as a source of continued injury and stimulus for intimal proliferation is avoided.

Coronary vessel perforation during balloon angioplasty: a case report

Coronary perforation can be managed with prolonged balloon inflations, covered stents, or embolization of the vessel. We report on a case of a balloon-induced perforation of the distal left anterior descending artery, that was sealed by injecting preclotted autologous blood through the balloon catheter lumen at the site of the perforation. The patency of the distal vessel was maintained.

Novel perfusion sleeve for use during balloon angioplasty: initial clinical experience

The perfusion sleeve (PS) is an "over-the-balloon" catheter designed to add perfusion capability to standard PTCA catheters. To evaluate the clinical effectiveness of this device, eight patients underwent standard PTCA with the PS retracted in the guide (Inflation 1-Control) and after deployment of the PS (Inflation 3-Control). Between standard inflations the PS was advanced and aligned with the already positioned PTCA balloon which was inflated for up to 15 minutes (Inflation 2-Perfusion). TIMI III flow was present in 5/7 and TIMI II flow in 2/7 patients during Inflation 2-Perfusion. Absolute ST segment shift (mm) on the ECG was significantly less at 3 minutes and prior to balloon deflation with the PS in place (1.0 +/- 1.4 and 1.1 +/- 1.1 mm) compared to Inflation 1-Control and Inflation 3-Control (2.6 +/- 1.3 and 2.3 +/- 0.3 mm) respectively (P < or = 0.05). Use of the PS in conjunction with standard PTCA is feasible, provides perfusion during prolonged balloon inflations and reduces the magnitude of ischemia.

Economic impact of angioplasty salvage techniques, with an emphasis on coronary stents: a method incorporating costs, revenues, clinical effectiveness and payer mix

OBJECTIVES

We sought to broaden assessment of the economic impact of percutaneous transluminal coronary angioplasty (PTCA) revascularization salvage strategies by taking into account costs, revenues, the off-setting effects of prevented clinical complications and the effects of payer mix.

BACKGROUND

Previous economic analyses of PTCA have focused on the direct costs of treatment but have not accounted either for associated revenues or for the ability of costly salvage techniques such as coronary stenting to reduce even costlier complications.

METHODS

Procedural costs, revenues and contribution margins (i.e., "profit") were measured for 765 consecutive PTCA cases to assess the economic impact of salvage techniques (prolonged heparin administration, thrombolysis, intracoronary stenting or use of perfusion balloon catheters) and clinical complications (myocardial infarction, coronary artery bypass graft surgery [CABG] or acute vessel closure with repeat PTCA). To assess the economic impact of various salvage techniques for failed PTCA, we used actual 1995 financial data as well as models of various mixes of fee-for-service, diagnosis-related group (DRG) and capitated payers.

RESULTS

Under fee-for-service arrangements, most salvage techniques were profitable for the hospital. Stents were profitable at almost any level of clinical effectiveness. Under DRG-based systems, most salvage techniques such as stenting produced a financial loss to the hospital because one complication (CABG) remained profitable. Under capitated arrangements, stenting and other salvage modalities were profitable only if they were clinically effective in preventing complications in > 50% of cases in which they were used.

CONCLUSIONS

The economic impact of PTCA salvage techniques depends on their clinical effectiveness, costs and revenues. In reimbursement systems dominated by DRG payers, salvage techniques are not rewarded, whereas complications are. Under capitated systems, the level of clinical effectiveness needed to achieve cost savings is probably not achievable in current practice. Further studies are needed to define equitable reimbursement schedules that will promote clinically effective practice.

Abrupt vessel closure: changing importance, management, and consequences

Percutaneous coronary interventions have been performed for 20 years. Despite the success and progress of these interventions, abrupt vessel closure has been a dramatic adverse event of coronary interventions. Closure has frequently led to the major complications of death, myocardial infarction, and emergency coronary artery bypass. Because of the fear of this adverse event and its subsequent complications, the applicability of coronary interventions is sometimes limited. The pathologic characteristics of abrupt vessel closure have been recognized as predominantly caused by dissection, with vessel recoil and thrombus formation playing important secondary roles. The recognition of the lesions at risk for abrupt vessel closure has led to a strategy of lesion-specific device therapy to reduce complications. Similarly the role of antiplatelet and antithrombotic therapies have reduced complications. The earliest methods of dealing with abrupt closure was emergency coronary artery bypass surgery with significant rates of morbidity and mortality. With the advent of second-generation devices and techniques, particularly stents, the management of abrupt vessel closure has been simplified and alternatives to emergency coronary bypass are more available. This article will review the history and current status of the prevention and management of abrupt vessel closure and demonstrate that anticipation and management of this complication have been facilitated with reduction of subsequent complications and increased applicability of coronary interventions.

New concept in coronary angioplasty: dilatation with a helical balloon that allows simultaneous autoperfusion

These preclinical studies investigate a new concept in coronary angioplasty and balloon catheter technology (the P100 catheter). The study sought to evaluate the morphology of experimental coronary arterial plaques dilated with the P100 in comparison to standard balloons, to determine the in vitro flow rates occurring during the inflation of the P100 in comparison to available perfusion catheters, and to assess the in vivo coronary flow velocity and the presence of ischemia during prolonged inflations with the P100. The development of myocardial ischemia is a major limitation of standard balloon angioplasty. To limit ischemia, autoperfusion catheters have been developed, in which blood flows through the balloon in the central catheter shaft. However, as the flow lumen profile is reduced to enhance the performance of these devices, so is the accompanying flow. An angioplasty catheter was designed to evaluate the feasibility of continuous autoperfusion around the dilatation balloon. The balloon surface was engineered to develop a helical trough for blood flow to occur during inflation. Arterial plaque morphology following angioplasty with the P100 (n = 8) and with standard balloons (n = 8) was evaluated in a swine model. In vitro flow rates during inflation of the P100 and available perfusion catheters were determined using 33% glycerol solution. In vivo coronary flow velocity was determined with a Doppler-tipped wire during 60-min continuous inflations with the P100, and 15-sec inflations with a standard balloon in 12 vessel segments in 7 dogs; using 3.0-3.5-mm-diameter balloons. All lesions were successfully dilated (< 50% luminal diameter stenosis) with the P100 and standard balloons. There were no morphologic differences in plaques dilated with P100 compared to standard balloons. In vitro flow rates with conventional 3.0-mm balloon perfusion catheters ranged from 27.1 +/- 2.1 ml/min (RX Flowtrack) to 38.7 +/- 0.9 ml/min (Stack Perfusion), P < .05. Flow with the P100 ranged from 54.8 +/- 4.3 ml/min (2.5-mm balloon) to 103.2 +/- 4.5 ml/min (3.5-mm balloon), P < .05. Distal average peak coronary flow velocity during prolonged P100 inflations varied from 69 +/- 7% of baseline at 5 min to 83 +/- 8% of baseline at 40 min, with an upward trend in velocity the longer the balloon was inflated. Hemodynamics remained stable. Experimental plaques are successfully dilated with a helical balloon by a mechanism that appears similar to the dilatation mechanism of standard balloons. These preclinical studies show that angioplasty and autoperfusion can be accomplished by a balloon that does not have complete surface area contact with the vessel wall. A gap created by the helix can thus provide a conduit for blood flow. Clinical studies will determine whether this innovation, which alters the tubular geometry of current angioplasty balloons, will provide autoperfusion and equivalent dilatation effects in human.

Abrupt (< 1 day), acute (< 1 week), and early (< 1 month) vessel closure at the angioplasty site. Morphologic observations and causes of closure in 130 necropsy patients undergoing coronary angioplasty

While abundant clinical and angiographic data are available regarding features of acute or abrupt closure at the site of balloon angioplasty, little morphologic information is available. This study discusses morphologic-histologic causes for acute closure after angioplasty in 130 necropsy patients. Intimal-medial flaps, elastic recoil, and primary thrombosis were the three leading morphologic causes for closure. Data were subdivided into time categories: abrupt (< 1 day), acute (< 1 week), and early (< 1 month). Intimal-medial flaps remained the most common cause for angioplasty closure despite time from angioplasty to documented occlusion. Morphologic recognition of types and frequencies of angioplasty closure are discussed, and specific mechanical, pharmacologic, or combined treatments are reviewed.

Hugging perfusion balloon salvage of a right coronary artery angioplasty

A case is described in which hugging balloons, one a perfusion and the other a non-perfusion balloon, were used to salvage a failed coronary angioplasty. A discussion concerning balloon combinations, techniques, and therapeutic options is included.

Management of idiopathic Budd-Chiari syndrome with primary stent placement: early results

PURPOSE

To evaluate the utility of primary stent placement in the management of Budd-Chiari syndrome (BCS) secondary to idiopathic inferior vena caval (IVC) obstruction.

PATIENTS AND METHODS

The case records of nine patients (four women, five men), ranging in age from 22 to 58 years (median, 26 years), with idiopathic IVC obstruction were reviewed. Hepatosplenomegaly, esophageal varices, and prominent collateral veins were found in all patients, while four also had ascites. Hepatic functional reserve was graded as Child class A in three patients and class B in the remaining six. All had at least one patent hepatic vein opening into the IVC below the site of occlusion. Percutaneous angioplasty of the IVC was performed, followed by the placement of double-skirt Gianturco-Rösch or hybrid Gianturco stents. Clinical follow-up was supplemented with duplex ultrasound (n = 8), endoscopy (n = 4), and cavography (n = 2).

RESULTS

Caval lesions were segmental. Revascularization was technically successful in all patients. The median pressure gradient across the lesion dropped from 38 mm Hg (range, 27-61 mm Hg) to 15 mm Hg (range, 10-20 mm Hg) (P = .008). Residual stenosis after stent placement ranged from 9% to 40% (median, 20%). One patient died of presumed pulmonary embolism; another patient experienced an episode of epistaxis. The procedure was followed by regression of signs and symptoms in the eight survivors. During the follow-up period (range, 3-31 months; median, 7 months) the IVC remained patent in all patients, and clinical features of BCS did not recur.

CONCLUSION

Primary stent placement could serve as the first line of treatment in patients with idiopathic BCS when the underlying lesion is not amenable to angioplasty.

Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty

Distal coronary hemoperfusion during percutaneous transluminal coronary angioplasty (PTCA)-with an autoperfusion balloon or active system-facilitates prolonged balloon inflation. Prolonged inflations may tack up intimal dissections and improve the primary angioplasty result in complex lesions. Additionally, distal perfusion may reduce the likelihood of cardiogenic shock during high-risk PTCA. Autoperfusion balloons are most frequently used to treat acute or threatened closure. There currently is no prospective clinical study showing that stent implantation for this complication is more successful and more cost-effective. The blood flow rates through autoperfusion balloons may not abolish myocardial ischemia, and higher flow rates can often be achieved with pumps. Therefore, during high-risk PTCA, pumps may be preferred to prevent hemodynamic collapse. Clinical application of perfusion pumps is hampered by the risk for mechanical hemolysis during prolonged perfusion and the high velocity of the bloodstream that exits the PTCA catheter, causing distal vessel wall trauma.

A new adjustable temporary stent catheter for management of acute dissection during balloon angioplasty

Acute coronary dissection remains a limitation of percutaneous transluminal coronary angioplasty. For the management of acute coronary dissection, a new adjustable temporary stent catheter that can be positioned to the lesion, deployed, and retrieved at a later stage was developed. This catheter has at its distal end a spiral stent that can be reduced and expanded in a controlled fashion by external manipulations. The adjustable temporary stent catheter was applied in three clinical cases with acute coronary dissection during balloon angioplasty. In all cases, the adjustable temporary stent catheter restored blood flow when it was expanded to the lesion for 60 min and this restoration was maintained after device removal. It is envisioned that this temporary stent device may prove a useful means for the treatment of acute coronary dissection during percutaneous transluminal coronary angioplasty.

Changes in patient treatment after abrupt closure complicating percutaneous transluminal coronary angioplasty: a historic perspective

This study compares the incidence and management of acute closure complicating coronary angioplasty in three historic populations of patients having undergone the procedure at the same center: group 1 (n = 146 of 881) ("early years" of angioplasty, 1980 to 1986), group 2 (n = 113 of 1781) (bailout stenting learning curve, 1990 to 1992), and group 3 (n = 34 of 525) (1993). The incidence of acute closure decreased from group 1 (146 [17%] of 881) to groups 2 and 3 (147 [6%] of 2306); (p < 0.001). Management of the occlusion changed over the years, with less emergency coronary bypass surgery ([36%] 52 of 146, 15 [13%] 113, and 3 [9%] of 34), respectively, p < 0.01) and more repeat angioplasty (70 [48%] of 146; 87 [78%], of 113, and 30 [88%] of 34, p < 0.001). The use of prolonged inflations (> 10 minutes) and stenting increased from group 2 (15 [13%] of 113 and 16 [14%] of 113, respectively) to group 3 (12 [35%] of 34, and 10 [30%] of 34, respectively). In-hospital death occurred in 18 (12%) of 146, 7 (6%) of 113), and (2 (6%) of 34) patients in the three groups. Acute myocardial infarction decreased from 64% to 46% and 27%, respectively (p < 0.01). Overall, the number of patients free of events at hospital discharge increased from 38 (26%) of 146 to 53 (47%) of 113 (p < 0.001) and to 23 (68%) of 34 (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Extensive intramural hematoma as the cause of failed coronary angioplasty: diagnosis by intravascular ultrasound and treatment by stent implantation

Dissections after coronary angioplasty are the major cause of ischemic events following percutaneous transluminal coronary angioplasty (PTCA) and may require additional measures such as intravascular stent deployment to relieve or prevent acute vessel closure. We describe a rare type of dissection after PTCA which caused a severe obstruction of the vessel segment proximal to the dilatation site without a visible dissection flap. Intravascular ultrasound was used to elucidate the morphology of the proximal vessel obstruction, which revealed an intramural hematoma extending into the proximal vessel segment as underlying mechanism. A Palmaz-Schatz stent was placed at the entry site of this hematoma, which led to the relief of the proximal vessel obstruction. After 3 months of anticoagulation therapy the repeat coronary angiography showed no significant restenosis. This demonstrates the unique insight into the underlying morphology of failed PTCA by intravascular ultrasound, which can help to manage even rare and unusual complications.

Initial experience with an intracoronary flow support device providing localized drug infusion: the Scimed Dispatch catheter

Two cases are presented illustrating the use of a new intracoronary infusion catheter providing flow support using a unique spiral coil design. Good clinical outcomes were obtained employing 4-hr inflations with localized infusion of urokinase at the site of dissection and extensive clot formation, respectively. This low-profile catheter-mounted device may provide an alternative to stent placement in cases of acute dissection complicated by thrombus formation.

Stand-by versus stent-by during percutaneous transluminal coronary angioplasty

To evaluate the impact of a more liberal use of endoluminal stenting on the incidence of emergency coronary artery by-pass grafting, we analyzed our attitude toward abrupt or threatened closure after percutaneous transluminal coronary angioplasty from 1986 through 1993. In 3083 procedures performed, 204 (6.6%) patients had abrupt or threatened closure. The incidence of closure or threatened closure remained stable during the 8 years, ranging between 5% (1986) and 8% (1987) (p = 0.89). Endoluminal stent implantation was attempted in 92 patients and successfully achieved in 90 (98%), and emergency bypass grafting had to be performed in 41 patients. The proportion without adverse end point (death or myocardial infarction) was higher in the patients treated by endoluminal stenting than in patients treated with bypass grafting (71/90 (79%) patients vs 17/41 (40%) patients, respectively; p < 0.0001). The use of bailout stenting gradually increased from 0.4% (1986) to 5.6% (1993) of all procedures (p = 0.0001), whereas the incidence of emergency bypass grafting decreased from 2.7% (1986) to 0.7% (1993) (p = 0.04). Meanwhile, the incidence of myocardial infarction remained stable between 5.6% (1988) and 1.8% (1992) (p = 0.1), and death rates decreased from 1.4% (1988) to 0.2% (1993) (p = 0.05). It is concluded that "stent-by" is a highly effective therapeutic approach (79% in the present study) toward closure after coronary angioplasty and that, although surgical "stand-by" is certainly mandatory for selected cases, routine stand-by is questionable.

Bailout Palmaz-Schatz coronary stenting in 39 patients with occlusive dissection complicating conventional angioplasty

The purpose of this study was to evaluate feasibility, safety, and efficacy of bailout Palmaz-Schatz stenting in a series of 39 patients with coronary dissection associated with acute or unequivocal threatened closure complicating conventional angioplasty. No anatomical characteristics other than reference vessel diameter < 3 mm were considered as contraindications for bailout coronary stenting. Stringent criteria were adopted in defining optimal results (< 10% residual stenosis, no angiographic evidence of residual dissection), suboptimal results (> 10% residual stenosis or angiographic evidence of residual dissection), deployment failure (failure to deploy the stent because of poor trackability or persistent occlusion despite stent deployment). A total of 49 stents and 7 half-stents were implanted in 36 patients (range 1-5; mean 1.45 +/- 0.84). Successful stenting without in-hospital death, urgent or semielective coronary surgery, stent thrombosis, or Q-wave myocardial infarction was achieved in 33/39 patients (85%). A suboptimal result was associated with an increased risk of in-hospital recurrence of ischemia and other related major adverse events (2/5 patients with suboptimal results vs. 1/31 patients with complete deployment success; P < 0.05). Multiple stents implantation did not carry a significant risk of major cardiac adverse events. The results of this study suggest that bailout Palmaz-Schatz stenting may be considered a stand-alone treatment of coronary dissection if an optimal acute angiographic result is achieved.

The role of the perfusion balloon catheter after an initially unsuccessful coronary intervention

Major dissection and acute closure following conventional percutaneous transluminal coronary angioplasty (PTCA) occur in 5%-10% of cases and lead to significant morbidity. Newer percutaneous modalities such as directional coronary atherectomy (DCA), excimer laser coronary angioplasty (ELCA), rotational ablation, and transluminal extraction atherectomy (TEC) can also be complicated by dissection and acute closure. Redilatation with conventional balloon catheters can reestablish patency of the artery or improve flow in a minority of cases. The perfusion balloon catheter (PBC) has several advantages over conventional balloon angioplasty in this situation. In approximately 70% of these cases, subsequent use of a PBC yields an acceptable clinical and angiographic result. The PBC permits rapid resolution of ischemia caused by acute closure or a flow-limiting dissection. New modifications of the PBC make it possible to position the catheter in nearly all segments of the coronary arterial tree including locations not accessible to other modalities, such as coronary stents or DCA, that are also used for salvage after a failed coronary intervention. Even if the PBC does not yield a definitive result, it allows rapid restoration of antegrade flow prior to coronary artery bypass grafting or coronary stent placement. Because of its ease of use, wide applicability, and efficacy, the PBC should be considered as the initial means of treatment in cases of major dissection or acute closure following any modality of percutaneous coronary revascularization.

Bailout coronary stenting with 6F guiding catheters for failed balloon angioplasty

Between July 1992 and February 1994, we attempted bailout Palmaz-Schatz stent implantation through a 6F guiding catheter after 52 failed coronary balloon angioplasty procedures to reverse (14 [27%] cases) or prevent (38 [73%] cases) abrupt vessel closure. The stents or half-stents were manually crimped onto a monorail balloon catheter for delivery. Thirty-nine (75%) procedures involved a single stent, and 13 (25%) involved two or three stents. Technical success was achieved in 50 (96%) procedures, and clinical success without major complications was obtained in 45 (87%) cases. Target vessel occlusion was documented angiographically or suggested clinically in 2 (4%) cases. Two (4%) patients underwent semielective bypass surgery, and in 4 (8%) patients a non-Q-wave and in 1 (2%) a Q-wave myocardial infarction developed. There were no deaths. Major bleeding occurred in 2 patients: 1 had an important groin hematoma that was treated with local surgery followed by coronary bypass surgery, and one had macroscopic hematuria that required interruption of anticoagulation therapy on day 4. Three (6%) femoral pseudoaneurysms were diagnosed by ultrasound and could be obliterated by external compression alone. Bailout coronary stent implantation through 6F guiding catheters after failed balloon angioplasty is technically reliable, safe, and cost-efficient. As a consequence, use of 6F guiding catheters is a good option for a large majority of routine balloon angioplasty procedures.

Emergency endoluminal stenting for abrupt vessel closure following coronary angioplasty: a randomized comparison of the Wiktor and Palmaz-Schatz stents

In order to compare the efficacy of two different stent types in case of bailout stenting, 65 patients, with abrupt or threatened vessel closure following coronary angioplasty, were randomly assigned to either Wiktor (Medtronic Inc., Minneapolis, MN, 33 patients) or Palmaz-Schatz (Johnson & Johnson Interventional, Warren, NJ, 32 patients) stent implantation. Stenting was technically feasible in all except one patient and immediately successful in reverting ischemia and vessel closure in 60 patients (92%). At hospital discharge, complication rates were comparable: early vessel closure, 18% (Wiktor) versus 13% (Palmaz-Schatz) (P = 0.53); any clinical event (such as death, myocardial infarction, and surgical revascularization): 18% (Wiktor) versus 22% (Palmaz-Schatz) (P = 0.71). At 6 months follow-up, these complication rates remained equal: restenosis, 38% (Wiktor) versus 27% (Palmaz-Schatz) (P = 0.42); any clinical and angiographic (vessel closure and restenosis) event: 45% (Wiktor) and 41% (Palmaz-Schatz) (P = 0.69). Baseline, direct postprocedural, and follow-up quantitative coronary analysis data were similar, with, however, an exception for the postprocedural residual stenosis [28% (24-32%) (Wiktor) and 21% (18-23%) (Palmaz-Schatz] (means and 95% confidence intervals). In conclusion, despite a discrete postprocedural angiographic benefit observed with the Palmaz-Schatz stent, the long-term clinical and angiographic outcome is similar in both treatment groups. The choice whether to implant a Wiktor or Palmaz-Schatz stent may probably be left to the discretion of the operator and his experience with one particular device.

Autoperfusion balloon versus stent for acute or threatened closure during percutaneous transluminal coronary angioplasty

Efficacy and major clinical end points were compared in 61 patients treated with a Stack autoperfusion balloon versus 36 patients who received a Palmaz-Schatz stent for acute or threatened closure during coronary angioplasty. The groups were comparable regarding baseline clinical characteristics. Procedural success was achieved in 43 patients (70%) treated with an autoperfusion balloon versus 34 patients (94%) who received a stent (p < 0.02). Emergency bypass surgery was performed in 13 patients (21%) with the autoperfusion balloon versus none of the patients with a stent (p < 0.001). In the stent group, 3 patients (8%) died (p < 0.05); 2 deaths were caused by thrombotic reclosure, and 1 patient died after unsuccessful stent delivery. Subacute reclosure during hospitalization occurred in none of the patients with autoperfusion versus 8 patients with the stent (22%) (p < 0.0002). Therefore, the number of patients with successful stent implantation at discharge decreased to 26 (72%). At 3-month follow-up in all patients with a successful intervention, reclosure or angiographic restenosis (> 50%) occurred in 13 patients with autoperfusion (30%) versus 3 patients with stents (12%) (p = NS). There was no difference in event-free survival during follow-up. Thus, both interventions were equally successful in the treatment of acute and threatened closure. More emergency surgery was performed in the autoperfusion balloon group, whereas a higher subacute reclosure rate was seen in the stent group. At 3-month follow-up, there were no significant differences regarding reclosure, restenosis, and event-free survival.

Temporary stents: the ACS RX flow support catheter

Although permanent stents have been successfully used as bail-out devices in the treatment of abrupt occlusion, the risk of stent thrombosis and of bleeding complications, as well as the cost of a prolonged hospitalization, have been deterrents to their universal acceptance. Temporary stents were conceived to provide internal scaffolding of the coronary arteries, which could stabilize occlusive dissections, yet still allow the stent to be removed before the time of peak incidence of subacute thrombosis. The ACS RX flow support catheter is a prototype temporary stent which has been recently evaluated in phase I and II clinical trials. The device is effective in improving angina score, coronary flow, and decreasing residual stenosis when used in cases of suboptimal percutaneous interventional results. However, the incidence of major complications and the need for adjunctive percutaneous interventions remain significant. Further studies are needed to define the optimal time of cage expansion as well as the clinical, anatomical, and procedural factors that predict efficacy and safety of this new device.

Hemoperfusion during coronary angioplasty: first European experience with a new hemoperfusion pump

Hemolysis tests with fresh human blood were performed in vitro with a new 5 ml, piston-type hemoperfusion pump, designed to prevent myocardial ischemia during coronary angioplasty. Despite driving pressures greater than 3 atmospheres, shear stress greater than 200 Pa, turbulent pump flow, and the presence of occlusive valves, hemolysis proved to be minimal. This effect is explained by the short amount of time that blood is subjected to mechanical forces that cause hemolysis in the system and by the small volumes of blood involved. During clinical application of the system, angina pectoris, electrocardiographic changes, and systemic blood pressure were used as parameters for myocardial ischemia. There was an effective reduction of ischemia during prolonged (10 min) balloon inflation, demonstrated by the absence of angina, minimal electrocardiographic changes, and normal blood pressure. In addition, the system proved to be safe and effective during high-risk angioplasty.

Microwave balloon angioplasty effectively seals arterial dissections in an atherosclerotic rabbit model

OBJECTIVES

The purpose of this study was to determine the effectiveness of microwave balloon angioplasty in sealing arterial dissections and to characterize the histologic features associated with this intervention.

BACKGROUND

Coronary dissection accompanying balloon dilation is frequently associated with abrupt closure and acute ischemic complications. Effective management of this complication remains an active area of investigation. Because thermal energy is effective in welding separated atherosclerotic plaques, a microwave-based catheter system that provides controlled local heating was utilized in vessels with angioplasty-induced dissections.

METHODS

Iliac artery dissections were induced in ahypercholesterolemic rabbit model. Vessels were randomly assigned to treatment with standard balloon angioplasty (control vessels) or microwave balloon angioplasty using an average temperature of 80 degrees C. The response of the artery was assessed angiographically and histologically.

RESULTS

Angiographic success, defined as a reduction of dissection length by > 50% or the resolution of lumen haziness, was achieved in 63% of microwave-treated vessels and in 16% of control vessels (p < 0.005). Dissection length (mean +/- SD) was reduced 8.0 +/- 4.8 mm in microwave-treated vessels compared with 0.1 +/- 7.9 mm in vessels receiving standard balloon inflations (p < 0.005). Cellular necrosis was more commonly observed in microwave-treated vessels than in control vessels (73% vs. 17%, p < 0.05), but less intraluminal thrombus was seen in vessels exposed to microwave energy (p < 0.05).

CONCLUSIONS

Microwave balloon angioplasty is more effective than routine balloon inflations in sealing arterial dissections in this model and appears to be less thrombogenic in these markedly disrupted vessels.

Pros and cons of perfusion balloons in failed angioplasty

Prolonged inflation with perfusion balloons is commonly used in failed angioplasty. The objective of this study was to determine the angiographic outcome of 59 consecutive patients treated with prolonged inflation with perfusion balloons as the primary treatment for failed angioplasty. Angiographic success (< 50% stenosis and normal flow) was achieved in 41%. Angiographic success was greater in the left anterior descending coronary artery (67% versus 33% for non-left anterior descending involvement, P = .044) and was less in complex dissections (25% versus 75% for no dissection or simple dissections, P = .025). Angiographic deterioration occurred in 37.5% of the successful group and 77% of the unsuccessful group (P = .002) and was more frequent in the right coronary artery (88% versus 50% for non-right coronary involvement, P = .007) and complex dissections (92% versus 38% for no dissection or simple dissections, P = .0001). Thus, in a group of patients with unsuccessful outcome following conventional balloon angioplasty, success with the perfusion balloon was modest. Furthermore, angiographic deterioration was frequently observed following unsuccessful prolonged inflation.

Incidence, predictors, and management of acute coronary occlusion after coronary angioplasty

Acute coronary occlusion occurs in 4.3% to 8.3% of patients during coronary angioplasty. Its occurrence is difficult to predict in an individual patient. At high risk are patients with unstable angina, intracoronary thrombus, extreme age, long complex lesions, and diffuse disease. "Standard" management including redilation (prolonged perfusion) thrombolytic treatment and emergency bypass surgery is only successful in approximately 50% of the patients and is associated with a high mortality and myocardial infarction rate of < 6% and 30%, respectively. Bail-out stent implantation appears to emerge as an effective alternative in suitable patients and might reduce mortality, the apparent progression to myocardial infarction, or might decrease the need for emergency bypass. New techniques including directional atherectomy, rotational ablation, or the excimer laser are associated with a similar frequency of acute occlusion. Immediate access to a surgical back-up facility remains necessary to treat refractory acute occlusions.

A randomized comparison of the effects of gradual prolonged versus standard primary balloon inflation on early and late outcome. Results of a multicenter clinical trial. Perfusion Balloon Catheter Study Group

BACKGROUND

Observational studies have suggested that prolonged balloon inflation during coronary angioplasty is associated with a high clinical success rate. This randomized clinical trial sought to evaluate the impact of primary gradual and prolonged inflations versus standard short dilatations in patients undergoing elective angioplasty.

METHODS AND RESULTS

In phase 1 of the study, patients were randomized to receive two to four standard (1 minute) dilatations or one or two prolonged (15 minutes) dilatations after a perfusion balloon had been placed across a single target lesion. Patients with unsuccessful angiographic appearance after phase 1 dilatations had further dilatations in phase 2. Patients were followed for 6 to 12 months after the procedure. Of 478 patients, 242 received a median of one prolonged dilatation of 15 minutes' duration, and 236 received three dilatations for a median of 1 minute. Patients assigned to prolonged dilatations had a higher success rate (< or = 50% residual visual stenosis) (95% versus 89%; P = .016), less severe residual stenosis by quantitative angiography (median [25th and 75th percentiles], 35% [26%, 42%] versus 38% [30%, 46%]; P = .001), and a lower rate of major dissections (3% versus 9%; P = .003) at the end of phase 1. A total of 114 patients had further dilatations in phase 2-43 in the prolonged arm and 71 in the standard arm. The final procedural success rate was 98% with both primary dilatation strategies, which included additional maneuvers such as prolonged dilatations in the patients randomized to the primary standard dilatation. Overall, 320 of 416 patients (77%) who were discharged after a successful procedure without any in-hospital event (death, myocardial infarction, coronary artery bypass graft surgery, abrupt closure, or repeat angioplasty in target vessel) returned for follow-up angiography. The restenosis rate (> 50% residual visual stenosis) was 44% (95% confidence interval, 37% to 52%) in the prolonged dilatation group and 44% (36% to 52%) in the standard dilatation group. The primary angiographic end point of failure at the end of phase 1, abrupt closure, or restenosis throughout the study period was similar in both groups (prolonged, 51%; standard, 49%; P = .62). The secondary end point of absence of clinical events (death, nonfatal myocardial infarction, coronary artery bypass graft surgery, or repeat angioplasty in target vessel) also was similar (prolonged, 66%; standard, 74%; P = .15).

CONCLUSIONS

Primary gradual and prolonged dilatations caused less arterial trauma with a modestly larger arterial lumen compared with standard dilatations. This initial improvement in angiographic appearance did not lead to a significant reduction in restenosis or clinical adverse events during follow-up.

Implantation and recovery of temporary metallic stents in canine coronary arteries

OBJECTIVES

The purpose of this study was to test the feasibility of implanting and retrieving a heat-activated recoverable temporary stent and to determine its effect on the angiographic, gross and histologic appearance of a normal coronary artery wall.

BACKGROUND

Permanent coronary stenting is associated with a significant incidence of thrombosis, bleeding and vascular complications. These may be avoided by temporarily stenting for a period of hours to several days.

METHODS

Seventy-eight stents constructed from the shape-memory nickel-titanium alloy nitinol were deployed by balloon expansion in the coronary arteries of 28 dogs and left in place for up to 6 months. Thirty minutes to 1 week after implantation, 70 stents were recovered by flushing the coronary arteries with 3 to 5 ml of 75 degrees C lactated Ringer solution, with collapse of the stent over a recovery catheter and subsequent withdrawal.

RESULTS

All stents were successfully recovered and removed percutaneously. Mean vessel diameter after stenting was 12 +/- 6% (p < 0.05) greater than baseline diameter. Mean vessel diameter after stent removal remained enlarged (6 +/- 3%, p < 0.05). No angiographic or gross evidence of thrombosis, dissection, embolization, migration or spasm was associated with implantation or recovery. Microscopic examination revealed minor intimal injury in 40 segments (51%). Microscopic focal medial necrosis was associated with mural platelet-fibrin thrombus in 23 stented segments (29%) and media was interrupted in 7 (9%).

CONCLUSIONS

This study demonstrates the feasibility of a new method of temporary stenting that uses the thermoelastic properties of nitinol to permit reliable recovery of the stent in normal canine coronary arteries.

Predictors of major ischemic complications after coronary dissection following angioplasty

Coronary dissection is a major cause of abrupt arterial closure after coronary angioplasty but may also be associated with no discernible event. Deciding which dissections should receive further treatment is often a dilemma if the artery remains patent. This case-control study examined predictors of major ischemic complications after coronary dissections. Fifty-eight patients with coronary dissections, but a patent artery at the completion of the angioplasty procedure, subsequently had in-hospital abrupt arterial closure, acute myocardial infarction, emergency coronary bypass surgery, or died; they were matched to 58 control subjects with dissection but no event. Analysis of each angiogram was performed with the examiner unaware of patient's history. Baseline angiographic and clinical characteristics of cases and controls were similar except for an excess of current smokers among the cases (31 vs 16%; p = 0.048). Residual luminal diameter at the dissection site was 1.2 +/- 0.6 mm (cases) versus 1.6 +/- 0.6 mm (controls; p = 0.001) with relative stenosis of 59 +/- 21% vs 43 +/- 21%, respectively (p = 0.0001). Dissections among cases were longer than among controls (11 +/- 7 mm vs 7 +/- 4 mm; p = 0.001). No significant difference was found in dissection morphology using 2 classification schemes or in final Thrombolysis in Myocardial Infarction study flow grade. Transient occlusion during the procedure, however, occurred in 47% of cases versus 5% of controls (p = 0.0001). Transient occlusion, residual percent stenosis > or = 70%, and dissections > or = 6 mm were independently predictive of major ischemic events.

Coronary and circulatory support strategies for percutaneous transluminal coronary angioplasty in high-risk patients

PTCA is now applied to patients with unstable acute ischemic syndromes, severe multivessel coronary artery disease, and impaired left ventricular function. To minimize the risk during angioplasty, several coronary and systemic circulation support approaches have been developed as adjuncts to high-risk angioplasty. Local coronary support techniques include the perfusion balloon catheter, the coronary stent, directional coronary atherectomy, laser balloon angioplasty, perfluorocarbon coronary perfusion, coronary sinus retroperfusion, and distal coronary hemoperfusion. Systemic circulatory support includes intraaortic balloon counterpulsation, cardiopulmonary support, the hemopump, and left heart partial bypass. These support devices, while associated with significant complications, may ultimately improve the safety of coronary angioplasty and allow its application to those who would otherwise not be candidates for revascularization.

Coronary stenting for treatment of acute or threatened closure following dissection after coronary balloon angioplasty

We studied 32 patients (age 58 +/- 9 years) who had been treated with a Palmaz-Schatz stent after significant dissection complicating percutaneous transluminal coronary angioplasty (PTCA). We attempted to cover the entire site of dissection with prosthesis. The presence of dissection after PTCA was associated with Thrombolysis in Myocardial Infarction grade 0 to 1 flow in 19 patients and grade 2 flow in 13. The stented arteries were: left anterior descending artery in 19 patients, right coronary artery in seven, and left circumflex artery in five. A single stent was implanted in 11 and multiple stents in 21 patients. Angiographic success was achieved in 30 patients (94%). Two patients (6%) had urgent coronary artery bypass graft surgery, two (6%) had a myocardial infarction, and one (3%) patient died. Subacute occlusion occurred in one patient (3%). Angiographic restenosis was found in three of nine patients (33%) with a single stent and 11 of 17 (65%) with multiple stents. Clinical follow-up at 11 +/- 3 months showed the necessity of coronary artery bypass graft surgery in two patients and repeat PTCA in nine (31%). We conclude that coronary stenting is an effective treatment for significant coronary dissection after PTCA with an acceptable incidence of major cardiac events at follow-up.