Myocardial protection during coronary angioplasty with an autoperfusion balloon catheter in humans

Myocardial Protection during Coronary Angioplasty with Autoperfusion and Forced Perfusion: An in vitro comparison

During coronary angioplasty, perfusion distal to the inflated angioplasty balloon can be maintained with autoperfusion balloon catheters and coronary perfusion pumps. The blood flow rates through the autoperfusion balloon catheters and the flow rates achieved with a perfusion pump were compared in vitro with fresh human blood at 37° C. In a specially designed system, blood flow rates through Stack™ autoperfusion balloon catheters were measured at 40, 60 and 80 mmHg continuous pressure. In another system, driving pressures were measured during perfusion with the pump, through a specially designed forced perfusion catheter at 20, 40 and 60 ml/min flow. The pressure applied in the autoperfusion experiments was converted into atmospheres (atm) to facilitate comparison with the driving pressures measured during pumping (1 mmHg = 1.316 × 10−3 atm). Mean flow rates through the autoperfusion balloon catheters were: 46 ml/min at 0.05 atm, 66 ml/min at 0.09 atm and 75 ml/min at 0.1 atm. Mean pressures during pumping were: 1.8 atm at 20 ml/min, 3.5 atm at 40 ml/min, 5 atm at 60 ml/min. Due to the phasic nature of coronary blood flow, the flow through autoperfusion balloons is generally lower than the minimum required for adequate myocardial protection (= 60 ml/min). Thus, autoperfusion balloon catheters are simpler and cheaper devices than perfusion pumps, but generally they are not able to provide adequate myocardial protection.

Outcome of prolonged balloon inflation for the management of coronary perforation

BACKGROUND

Coronary perforation (CP) is a rare, sometimes lethal complication of percutaneous coronary intervention (PCI).

OBJECTIVES

The purpose of this study was to review the cases of CP and to investigate the management after CP.

METHODS

A total of 3469 PCIs were performed in our institution from April 1999 to April 2008. All CP cases were identified from our computerized database.

RESULTS

Thirty patients were identified as having CP (0.86%). According to the Ellis classification, we determined the grade of perforation as type I in 17 cases (56%), type II in 2 cases (7%), and type III in 11 cases (37%). Most CPs were caused by wires (53%), while balloons, stents, and atherectomy devices were responsible for 7%, 37%, and 3%, respectively. Wire caused only 1 case of type III CP (6%), while stent caused 9 type III CPs (82%, p<0.01). Four patients (36%) with type III CP required urgent coronary artery bypass graft surgery (CABG), while no patient with type I/II CP required it (p<0.01). Prolonged balloon inflations were effective for 8 cases out of 11 stent CPs, however, the ballooning duration was significantly longer than that in wire and balloon CP (44±37min vs. 21±13min, p<0.05).

CONCLUSIONS

Stent CP often causes type III CP and one third of type III CP required urgent CABG. Although stent CP required longer balloon inflations for the management, prolonged balloon inflation might be useful for the management even in the stent CP.

Atrial natriuretic peptide augments coronary collateral blood flow: a study during coronary angioplasty

BACKGROUND AND HYPOTHESIS

In vitro studies have shown that atrial natriuretic peptide (ANP) causes relaxation of preconstricted blood vessel strips and inhibits the contraction of isolated vessels in response to norepinephrine and angiotensin II. The present study examined the effects of exogenous ANP on the coronary collateral blood flow during angioplasty.

METHODS

We studied 15 patients undergoing elective balloon angioplasty during the second and third balloon inflations. A Doppler flow guidewire was advanced distal to the lesion and used for the estimation of coronary blood flow velocity. After the second balloon inflation, 25 ng/kg/min of ANP were administered intracoronarily for 8 min. Electrocardiogram, pressure, and flow velocity were recorded immediately before each balloon deflation. Fourteen other patients served as controls and received normal saline infusion.

RESULTS

Velocity time integral increased from 65 +/- 40 to 79 +/- 46 mm (p < 0.05) during the third balloon inflation, whereas ST deviation decreased from 1.3 +/- 0.9 to 0.7 +/- 1.0 mV (p < 0.05). These variables did not change in the control group during the two tested balloon inflations.

CONCLUSION

Exogenous ANP augments coronary collateral blood flow and ameliorates myocardial ischemia during angioplasty.

Long-Term Prediction of Mortality in Elderly Persons by Dobutamine Stress Echocardiography

BACKGROUND

Dobutamine stress echocardiography (DSE) was shown to provide incremental prognostic information. However, its role in the prediction of mortality in elderly persons is not well defined. We assessed the value of DSE in the prediction of mortality and hard cardiac events during long-term follow-up in patients older than 65 years.

METHODS

We studied 1434 patients >65 years old (mean age 72 +/- 3 years) who underwent DSE for evaluation of coronary artery disease. Ischemia was defined as new or worsening wall motion abnormalities. Follow-up events were total mortality and hard cardiac events (cardiac mortality and nonfatal myocardial infarction). Multivariable Cox regression analysis was used to identify the independent predictors of follow-up events.

RESULTS

Ischemia was detected in 675 patients (47%). Five hundred six patients (35%) had a normal study, and 253 (18%) had fixed wall motion abnormalities. During a mean follow-up of 6.5 years, 532 (37%) deaths occurred, of which 249 (17%) were due to cardiac causes. A nonfatal myocardial infarction occurred in 45 patients (3%). Independent predictors of all-cause mortality in a multivariate analysis model were age (hazard ratio [HR] 1.06; 95% confidence interval [CI], 1.05-1.08), male sex (HR 1.5; 95% CI, 1.2-1.8), hypertension (HR 1.2; 95% CI, 1.1-1.4), smoking (HR 1.3; 95% CI, 1.1-1.6), diabetes (HR 1.4; 95% CI, 1.1-1.8), rest wall motion abnormalities (HR 1.07; 95% CI, 1.06-1.09), and ischemia (HR 1.3; 95% CI, 1.1-1.6). Independent predictors of hard cardiac events were age (HR 1.07; 95% CI, 1.05-1.09), male sex (HR 1.3; 95% CI, 1.1-1.7), smoking (HR 1.3; 95% CI, 1.1-1.6), diabetes (HR 1.6; 95% CI, 1.2-2.2), rest wall motion abnormalities (HR 1.13; 95% CI, 1.12-1.16), and ischemia (HR 2.1; 95% CI, 1.5-2.8).

CONCLUSION

DSE provides independent prognostic information to predict all-cause mortality and hard cardiac events in elderly patients.

Coronary angioplasty performed using the FullFlow mechanical dilatation-perfusion catheter: initial animal experience

We report our initial experience with an animal model, using a new mechanical catheter-based dilatation system, the FullFlow (FF) catheter. The primary purpose of this study was to compare coronary flow achieved using the FF perfusion catheter and a traditional balloon angioplasty perfusion catheter. Baseline average peak velocity (APV) measurements were obtained using the FloWire Doppler guide wire. Either a Surpass Perfusion balloon (PB) or an FF catheter was advanced to a coronary segment. Doppler measurements were made before, during, and after full device expansion. Simultaneous heart rate, EKG, and blood pressure readings were recorded. Significant 36.1% and 29% reductions in mean APV were found for PB when comparing baseline to device-up measurements and when comparing device-down to device-up measurements, respectively. In contrast, significant 12.2% and 18.5% increases were seen in mean APV for the FF. No significant differences were found in heart rate, systolic blood pressure, diastolic blood pressure, or ST-segment changes. The FF system produces superior downstream coronary perfusion with side-branch coronary patency compared with results using a contemporary perfusion balloon angioplasty catheter.

Autoperfused balloon catheter for intravascular MR imaging

An intravascular magnetic resonance (MR) imaging catheter for high-resolution imaging of vessel walls was developed. The catheter design is based on an autoperfusion balloon catheter that allows passive perfusion of blood during balloon inflation. The blood enters a central lumen through multiple sideholes of the catheter shaft proximal to the balloon. A remotely tuned, matched, and actively decoupled, expandable single-loop radiofrequency coil was mounted onto the balloon to receive intravascular MR signals. The autoperfusion rate through the catheter was determined experimentally relative to perfusion pressure. The catheter concept was evaluated in vitro on human femoral artery specimens and in vivo in the internal carotid artery of two pigs. The proposed catheter design allowed for maintained blood perfusion during the acquisition of high-resolution intravascular images. During perfusion, image quality remained unaffected by flow, motion, and pulsatility artifacts. The availability of an autoperfused intravascular catheter design can be considered an important step toward high-resolution atherosclerotic plaque imaging in critical vessels such as the carotid and coronary arteries.

Comparison of immediate and in-hospital results of conventional balloon and perfusion balloon angioplasty using intracoronary ultrasound

Angiographic studies have demonstrated that perfusion balloon percutaneous transluminal coronary angioplasty (PTCA) may result in modestly improved luminal gains and fewer major dissections than conventional balloon PTCA. However, intracoronary ultrasound (ICUS), which is more sensitive than angiography in evaluating the incidence, extent, and severity of dissection, was not used. We randomized 48 patients with 54 coronary stenoses to conventional or perfusion balloon PTCA. Four 2-minute inflations were permitted with conventional balloon PTCA. Two 10-minute inflations were allowed with perfusion balloon PTCA. Quantitative coronary angiography and ICUS were performed before and after treatment. In-hospital clinical events were recorded. Conventional and perfusion balloon PTCA achieved similar improvements in lumen diameter (1.25+/-0.51 vs 1.28+/-0.51 mm) and reductions in percent stenosis (-45+/-21% vs -44+/-15%) by quantitative coronary angiography. Comparable gains in lumen diameter (0.62+/-0.39 vs 0.50+/-0.38 mm) and lumen area (2.70+/-1.96 vs 2.05+/-1.52 mm2) were observed on ICUS. Angiography demonstrated similar rates of any dissection (36% vs 21%) and major dissection (12% vs 7%). ICUS identified a similar incidence of any dissection (60% vs 76%) and type II dissection (52% vs 62%). The relative dissection area was also similar (9.2+/-5.6% vs 7.8+/-5.8%). One conventional balloon patient experienced postprocedural chest pain. No patient in either group died, or had myocardial infarction, abrupt closure, or urgent revascularization.

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.

Selective suction and pressure-regulated retroinfusion: an effective and safe approach to retrograde protection against myocardial ischemia in patients undergoing normal and high risk percutaneous transluminal coronary angioplasty

OBJECTIVES

We sought to study the safety, feasibility and efficacy of selective suction and pressure-regulated retroinfusion to protect against myocardial ischemia in patients undergoing normal risk and high risk balloon angioplasty.

BACKGROUND

In a pig model of acute myocardial ischemia it was previously shown that use of selective suction and pressure-regulated retroinfusion was able to substantially preserve regional myocardial function during ischemia with a higher efficacy than that obtained with unselective synchronized retroperfusion.

METHODS

In 42 patients with normal risk (n = 27) or high risk (n = 15) percutaneous transluminal coronary angioplasty (PTCA), alternate balloon inflations of the left anterior descending coronary artery (60 s) were either supported or not supported by selective suction and pressure-regulated retroinfusion of the anterior interventricular vein. In an additional group of 10 patients with normal risk, retroinfusion was directly compared with autoperfusion during 10 min of ischemia.

RESULTS

Balloon inflations without retroinfusion resulted in a decrease of regional myocardial function in the ischemic zone to 13% of baseline. In contrast, regional myocardial function was preserved at 76% of baseline (p < 0.05) during balloon inflation supported by retroinfusion. This preservation of regional myocardial function by retroinfusion was maintained during 10 min of ischemia with at least similar efficacy compared with autoperfusion. With retroinfusion, hemodynamic variables were stabilized in normal risk and high risk patients. No complications related to the catheterization of the anterior interventricular vein using a femoral approach (95% success rate) were observed, and clinical follow-up after 3 to 6 months was uneventful with regard to the coronary intervention.

CONCLUSIONS

Use of selective suction and pressure-regulated retroinfusion was feasible and safe and had a high efficacy for preserving regional myocardial function and hemodynamic variables during PTCA in normal risk and selected high risk patients.

1998 SCVIR Gary J. Becker Young Investigator Award. Endovascular repair of arterial pseudoaneurysms with use of a perfusion balloon catheter

PURPOSE

Pseudoaneurysms represent contained disruption of the arterial wall. Iatrogenic pseudoaneurysms frequently complicate complex endovascular procedures. With use of an animal model, the authors attempted to determine the safety and efficacy of using a perfusion balloon catheter (PBC) to thrombose surgically created pseudoaneurysms.

MATERIALS AND METHODS

An in vitro system measured maximum flow volume through a 5-F PBC. Pseudoaneurysms were created in domestic swine with use of a jugular vein patch anastomosed to a femoral arteriotomy. The PBC was inflated across the pseudoaneurysm neck for 30-minute intervals until thrombosis was confirmed by ultrasound. Completion arteriography was performed to evaluate for vascular complications.

RESULTS

Maximum flow through the PBC was 62.6 mL/min measured at a constant pressure gradient of 120 mm Hg. Five pseudoaneurysms were created in four animals. The PBC completely thrombosed all five lesions. The mean treatment duration was 129 minutes (+/- 39 minutes SD). No native arterial injury, in situ thrombus, or distal embolization occurred. Partial recanalization of three of the five treated pseudoaneurysms was identified on follow-up arteriography and gross sectioning (n = 2 and n = 1, respectively).

CONCLUSION

The PBC safely and effectively thrombosed surgically created pseudoaneurysms. Partial recanalization of treated pseudoaneurysms was demonstrated. Clinical trials are warranted.

Evaluation of an active coronary perfusion balloon device using Doppler flow wire during PTCA

The aim of this study was to assess whether active coronary perfusion catheters (APC) can provide a sufficient coronary flow in large caliber vessels during balloon inflation. To prevent myocardial ischemia during PTCA, these APC may be employed. However, it is as yet unknown whether the active flow rate of these devices approaches the flow rate prior to PTCA during balloon inflation. Therefore, we measured the efficacy of the APC during balloon inflation in vessels supplying a large amount of myocardium. In 12 patients (1 female, 11 males, 53 +/- 12.6 yr) with stenosed vessels (average diameter 3.4 +/- 0.26 mm), the coronary flow velocity was measured using a 0.014" Doppler guidewire, which was placed distally bypassing the balloon of the APC. The active perfusion balloon catheter was advanced through a 7F guiding catheter along a 0.014" guidewire. After removal of the guidewire, arterial blood being withdrawn from the side port of the femoral angioplasty sheath was pumped through the catheter to the distal coronary vessel. The perfusion volumes of the pump were set to different levels between 30 to 60 ml/min. Intracoronary flow rate was calculated by the angiographically assessed vessel luminal area [symbol: see text] average peak velocity [symbol: see text] 0.5. The mean coronary flow rate prior to PTCA was 43 +/- 17.7 ml/min. Maximum flow during PTCA was 55 +/- 19.6 ml/min. We found a good correlation between the preset external pump rate and the coronary flow in situ (r = 0.92). Pre-PTCA flow rates were achieved in 11 of 12 patients (92%) during balloon inflation. No relevant decrease in the arterial pressure occurred during dilation times of 4.6 +/- 1.63 min. Only two patients showed significant ECG changes during these balloon inflations. After an average follow-up period of 13 +/- 6.3 mo, only one patient (8%) had a significant re-stenosis requiring the implantation of a stent. The combination of intravascular Doppler velocity measurements with quantitative coronary angiography offers the opportunity of exact online flow registration during angioplasty. Using APC, It is possible to maintain a sufficient coronary flow in the distal vessel during balloon inflation even in large vessels. Therefore, as compared with mechanical circulatory assist devices, coronary assist by APC is a little invasive, but according to our measurements it might be a sufficient tool for performing PTCA also in high-risk patients.

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.

Coronary artery angioplasty with a helical autoperfusion balloon catheter

The initial in-hospital and long-term clinical experience with a helical autoperfusion balloon catheter in the treatment of coronary artery disease is reported. This new catheter design allows blood to flow passively around the inflated balloon through a protected helical channel molded into the balloon surface. Twelve consecutive patients underwent PTCA. Continuous ST monitoring, heart rate, average peak distal coronary blood flow velocity (APV), coronary blood flow (CBF), dP/dt and systemic and pulmonary arterial pressures were determined during PTCA. During balloon inflation there were no hemodynamic changes, TIMI flow was 1.7 +/- 0.8, and APV was 39% of baseline. Luminal diameter stenosis improved from 61 +/- 17 to 29 +/- 13% (P < 0.05) following PTCA. Mean continuous inflation duration was 385 +/- 215 sec and 6/12 patients had > or = 7.5-min inflations. There were no in-hospital adverse cardiac events. One patient developed recurrent angina during 8 mo of follow-up and underwent successful PTCA of a restenotic lesion. We conclude that human plaques can be successfully dilated with a helical balloon catheter that provides autoperfusion and the ability to perform prolonged inflations with hemodynamic stability. A comparison of this PTCA catheter with standard balloon catheters is warranted.

Intracoronary stent implantation using a single high-pressure perfusion balloon catheter

Currently, the recommended strategy for Palmaz-Schatz intracoronary stent implantation is to use two balloons: an undersized balloon for predilation to facilitate a channel for the stent and a high pressure balloon for postdilation to obtain good apposition of the struts into the vessel wall. We reported our experience using the perfusion balloon as the initial balloon to dilate intracoronary lesions and demonstrated a reduction in the total number of balloons used per angioplasty procedure. The objective of this study was to examine whether a single balloon could effectively be used for stent implantation. The study population included 95 patients who underwent elective intracoronary stent placement to 100 lesions using 110 Palmaz-Schatz stents by nine individual operators. Lesions were predilated with an ACS RX LIFESTREAM balloon at a low pressure of 4-6 atm (mean 5.7 +/- 2.6). After stent deployment, the same balloon was used at a high pressure (mean 16.2 +/- 1.2). Mean balloon size, which was chosen as the stent size, was 3.4 +/- 0.4 mm. Comparison of this strategy with the recommended strategy of 68 consecutive elective stent deployments at a single center during the same time was performed. Stent implantation using a single balloon strategy was angiographically successful in 99 of 100 (99.0%) lesions. The single balloon strategy was associated with a balloon burst rate of 9.1%. The number of balloons used per stent deployment was 1.2 vs. 2.4 using the recommended strategy (P < 0.0001). There was no evidence of stent thrombosis, any MI, or target lesion revascularization during the procedure and hospitalization. One in-hospital death as a result of nonhemorrhagic stroke was documented in the treated group. We concluded that using a single high pressure perfusion balloon for pre and postdilation in patients undergoing elective stent placement is safe and reduces the number of balloons used per procedure.

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.

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.

Changing outcome of angioplasty in the elderly

OBJECTIVES

This study sought to determine whether in-hospital and intermediate-term posthospital outcomes have changed in elderly patients undergoing percutaneous transluminal coronary angioplasty from the period 1980 through 1989 to the period 1990 through 1992.

BACKGROUND

Although elderly patients have a higher incidence of procedure-related deaths and late recurrence of angina after coronary angioplasty, recent complication rates for angioplasty seem to be lower.

METHODS

From 1980 to 1989, 982 patients > or = 65 years old underwent nonemergent coronary angioplasty (group A). They were compared with 768 similar patients who had coronary angioplasty from 1990 to 1992 (group B).

RESULTS

Patients in group B were older than those in group A and had a higher mean concomitant disease score, a higher proportion of men and a greater proportion of patients with a previous myocardial infarction and previous coronary artery bypass surgery. Despite the increased complexity of the group B cohort, procedural success rates were higher, and rates of important in-hospital complications were much lower than those in group A. For group A versus group B, respectively, the technical success rate was 88.1% versus 93.5% (p < 0.001), in-hospital death rate 3.3% versus 1.4% (p = 0.014), emergency bypass surgery rate 5.5% versus 0.65% (p < 0.001) and incidence of in-hospital death or myocardial infarction 6.3% versus 3.4% (p < 0.005). However, intermediate-term posthospital event-free rates in hospital survivors did not decrease. The rate of death or myocardial infarction at 6 months was 4.7% in group A versus 7.1% in group B (p < 0.05). Survival free of acute myocardial infarction, bypass surgery, repeat coronary angioplasty or severe angina at 1 year was 66.7% in group A versus 54.9% in group B (p < 0.001). The combined in-hospital death/myocardial infarction rate plus that for the first 6 months after hospital dismissal was essentially equivalent for the two groups (10.3% vs. 9.9%, p = NS).

CONCLUSIONS

An increase in technical success rates and a reduction in short-term complication rates for coronary angioplasty in the elderly in recent years have not translated into an improved event-free survival rate, which continues to be influenced by important baseline characteristics of these high risk patients.

Autoperfusion balloon catheter for treatment of vertebral artery stenosis

Percutaneous transluminal angioplasty (PTA) of the vertebral artery was performed with an autoperfusion balloon catheter in five patients. There were no complications in the form of embolic episodes or neurological deficits due to brain ischaemia during inflation. In critical cases with insufficient collateral circulation during temporary occlusion, the use of an autoperfusion balloon catheter may expand the indications for PTA in patients with ischaemic cerebrovascular disease.

Functional characteristics of a new coronary perfusion balloon: comparison with the Flowtrack 40 in closed chest swine

This study was designed to compare a new investigational coronary perfusion balloon (Wave, Scimed Life Systems Inc.) with that of an approved, widely used, current generation device (Flowtrack 40, Advanced Cardiovascular Systems). Domestic swine were anesthetized with pentobarbital and instrumented using standard percutaneous technique. Left ventricular contractile function (dP/dt) was monitored using a micromanometer while intracoronary and surface ECGs were also recorded. Eight target vessels were studied (4 LAD and 4 Cx) in random order. The perfusion balloons were kept inflated for 10 min. Complete coronary occlusion with a standard angioplasty balloon produced marked decreases in mean aortic pressure, left ventricular developed pressure, peak +dP/dt, peak -dP/dt, and significant ST segment elevation in both intracoronary and surface ECG at 30 seconds. Neither the Wave or Flowtract 40 produced any change in heart rate or mean aortic pressure. Both catheters caused a drop in left ventricular developed pressure immediately after balloon inflation. At 10 min, however, there was a small but significant decrease only with the Flowtrack 40. Similarly, peak +dP/dt was slightly depressed during Flowtrack 40 inflation at 10 min but not with the Wave catheter. Both catheters produced ST segment elevation on the surface and intracoronary electrocardiographic records. These changes were significantly greater with the Flowtrack 40 system. Thus, both the Flowtrack 40 and Wave perfusion balloons are effective in preventing ischemia during coronary occlusion in swine; however, the latter system may be more effective in this model.

Perfusion therapy to reduce myocardial ischemia en route to emergency coronary artery bypass grafting for failed percutaneous transluminal coronary angioplasty

Despite improvements in operator technique, catheter technology, and the development of new devices, emergency coronary artery bypass grafting (CABG) is still required in 1%-4% of attempted catheter based revascularization procedures. Patients who require such emergency CABG after failed percutaneous transluminal coronary angioplasty (PTCA) have worse acute outcomes than those undergoing elective CABG, with a higher incidence of Q wave myocardial infarction (MI) and a higher operative mortality. In patients with otherwise refractory abrupt closure, maintenance of antegrade coronary blood flow using perfusion catheters lessens the incidence of Q wave MI and lowers peak creatinine phosphokinase. Direct maintenance of coronary flow thus appears to provide more definitive control of myocardial ischemia than purely adjunctive measures, such as intra-aortic balloon pumping, cardiopulmonary support, or coronary sinus retroperfusion. Although the recent introduction of coronary stents holds great promise for definitive percutaneous reversal of abrupt closure and a dramatic decrease in the incidence of emergency CABG for failed PTCA, maintenance of antegrade flow via perfusion technology remains the cornerstone of management in reducing the perioperative mortality and morbidity of patients who still require emergency bypass surgery after failed PTCA.

Alterations in reference vessel diameter following intracoronary stent implantation: important consequences for restenosis based on percent diameter stenosis

The scaffolding effect of stent implantation has the potential to alter vascular geometry and dimensions. The objective of this study was to determine the impact of intracoronary stent implantation on the reference vessel diameter and the consequences of this on the frequency of restenosis applying the binary definitions of restenosis based on percent diameter stenosis. Routine angiographic follow-up was performed in 79/80 consecutive patients who had a single elective Palmaz-Schatz stent implanted in denovo lesions in native coronary arteries 6.5 +/- 3.4 mo after the index procedure. Complete quantitative angiographic follow-up was available in 78 (98%). The mean reference vessel diameter was 2.9 +/- 0.6 mm preprocedure, increased to 3.1 +/- 0.5 mm immediately poststent implantation and was 2.6 +/- 0.6 mm at follow-up (F = 6.45, P = 0.0001, ANOVA for repeated measures). In view of the varying reference vessel diameter, percent diameter stenosis postangioplasty and at follow-up was determined by two methods: (1) automatically by the quantitative coronary angiographic analysis system and (2) by expressing the minimal luminal diameter postangioplasty and at follow-up as a function of the original preprocedural reference vessel diameter. The restenosis rate was significantly greater for all definitions of restenosis when the minimal luminal diameter was determined as a function of the original preprocedure reference vessel diameter (e.g., 34% vs. 18% for the > or = 50% criterion, P = 0.018). Stent implantation results in alterations in reference vessel diameter, which have important consequences for the frequency of restenosis presented as a binary variable based on percent diameter stenosis.

Efficacy and safety of using perfusion dilatation catheter as initial balloon in coronary angioplasty

The efficacy and safety in using a new low-profile perfusion balloon catheter (PBC) as the initial balloon in percutaneous coronary angioplasty (PTCA) was assessed retrospectively in 61 patients: 43 males, mean age 62 +/- 12 years. Thirty-three patients (54%) had unstable angina. PTCA was performed using an improved PBC in the following vessels: LAD 40%; CX 21%; RCA 24%. Lesion morphology was: Type A 21%; Type B1 18%; Type B2 40%; Type C 21%. Mean artery size was 3.01 +/- 0.53 mm. Mean PBC size was 3.14 +/- 0.45 mm. The mean number of inflations used was 2.85 +/- 2.0. The mean longest inflation was 415 +/- 213 sec and the total inflation time was 663 +/- 342 sec to a mean maximum pressure atmosphere of 7.85 +/- 2.0 bars. The number of balloons used per procedure was 1.2 +/- 0.44. In 50 patients (82%) only one balloon was used during the PTCA. PTCA was successful (< 50% diameter stenosis without major complications) in 60 patients (98.4%). Mean diameter stenosis at baseline was 82 +/- 9.5% and post-angioplasty 13 +/- 10.6%. A mild intimal tear occurred in 6 patients (9.8%). A stent was implanted in 3 patients (4.9%) due to severe dissection. In hospital reocclusion occurred in one patient (1.6%). There were no deaths or emergency bypass surgery. A low profile PBC is safe and effective as an initial balloon in PTCA. It may reduce the number of balloons used and inflations per procedure.

Double perfusion system for coronary angioplasty at the origin of the main vessel

For the treatment of stenosis near the origin of either the left anterior descending artery or the left circumflex artery, one autoperfusion catheter was used to dilate the lesion while another was used to maintain perfusion of the nonstenosed vessel, which would normally suffer from a decrease in blood flow. This technique was applied to nine procedures in six patients. The balloon could be inflated for more than 60 sec in all cases. Satisfactory dilation was achieved without a significant decrease of systemic blood pressure during the procedure.

Fracture of a perfusion balloon catheter during coronary angioplasty

In a 74-year-old patient with increasing angina, an attempt was made to dilate an ostial stenosis in the first diagonal artery. The initial attempt with a long balloon catheter was unsuccessful. Because of chest pain associated with hypotension during balloon inflations, a second attempt with a perfusion balloon catheter resulted in fracture of this catheter's tip (14 mm long) in the artery. Bypass graft surgery was performed and the retained fragment was easily removed by arteriotomy. The patient made an uneventful recovery.

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.

Cardiovascular applications of fluorocarbons: current status and future direction--a critical clinical appraisal

Alteration of normal blood flow to the heart may result in myocardial ischemia or infarction. Perfluorochemical emulsions offer a potential means to improve oxygenation of the heart during periods of hypoxia. The small particle size and linear disassociation curve of perfluorochemicals may result in greater oxygen delivery than blood particularly in severely diseased or damaged atherosclerotic vessels. Intracoronary Fluosol given during PTCA reduces the myocardial ischemia which occurs during balloon inflation. Although Fluosol does not prevent myocardial dysfunction during prolonged balloon inflations, new concentrated perfluorochemicals have increased oxygen delivery capacity and may have greater benefit. Experimentally, during coronary occlusions, perfluorochemicals promote higher oxygen tension in areas of ischemia and result in infarct size reduction. Reduction of oxygen free radicals has been proposed as the mechanism by which Fluosol exerts its ability to reduce infarct size. Clinical studies with Fluosol and thrombolytic therapy for treatment of acute myocardial infarctions are ongoing to assess ability to preserve myocardial function. Perfluorochemical cardioplegia can deliver oxygen during periods of cardiac arrest and may improve immediate post CPB myocardial function particularly in those patients with pre-existing left ventricular dysfunction. The oxygen-carrying capacity of perfluorocarbons and its unique properties offer great advantages to improve the treatment of cardiovascular diseases.

Coronary angioplasty using an autoperfusion balloon catheter through a 6 French guiding catheter

Use of 6 French guiding catheters for elective percutaneous transluminal coronary angioplasty has been limited by lack of a compatible autoperfusion balloon catheter for management of complications such as acute vessel closure and large subintimal dissections. We describe the successful use of a lower profile autoperfusion balloon catheter through large internal lumen 6F guiding catheters for elective coronary angioplasty. These cases demonstrate the feasibility of the use of autoperfusion balloon catheters with 6F guiding catheters in elective, and presumably also in emergent, settings.

Recent changes in the management and outcome of acute closure after percutaneous transluminal coronary angioplasty

The major cause of morbidity and mortality associated with percutaneous transluminal coronary angioplasty (PTCA) is acute closure. This study compared the clinical outcome of 2 groups of patients who experienced acute closure during PTCA. One group was treated during a period when intracoronary stents, laser balloons and perfusion balloons were available for treatment of acute closure (group II). These results were compared with the clinical outcome a group of similar patients who were treated for acute closure during a period that immediately preceded the availability of these devices (group I). One hundred sixty-six patients had acute closure in group I, whereas 156 patients experienced acute closure in group II. Baseline clinical characteristics were similar for both groups. There was no difference in ejection fraction, number of vessels diseased, degree of stenosis or number of vessels attempted between the 2 groups. Patients in group II had more balloon inflations and longer balloon inflation times when compared with patients in group I. Of the 156 patients in group II, 47% were treated with either an intracoronary stent, laser balloon or perfusion balloon. Group II patients had fewer Q-wave myocardial infarctions (9.1 vs 20.3%, p = 0.005). In addition, peak creatine phosphokinase levels (826 +/- 1,515 vs 517 +/- 1,050, p < 0.01) and mean residual stenosis (40.7 +/- 33.2 vs 58.0 +/- 34.4%, p < 0.0001) were also lower in group II patients. There was also less coronary artery bypass grafting during the same admission (38.6 vs 29.5%, p = 0.02) in group II patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Thermal-perfusion balloon coronary angioplasty: in vivo evaluation

The goal of this study was to develop and test a new radio frequency thermal balloon system to allow longer balloon inflations at lower temperature levels than have been used with standard (laser) thermal balloon angioplasty. Radio frequency thermal capabilities were combined with perfusion balloon technology, creating a thermal-perfusion balloon catheter system for prolonged thermal inflations. Twenty-five dogs underwent thermal-perfusion angioplasty at 37 degrees, 60 degrees, or 80 degrees C for 1.5, 5, or 15 minutes with angiographic and morphologic assessments at 24 hours (n = 17) or 4-6 weeks later (n = 8). Treated segments and side branches remained patent. No coronary spasm, occlusive thrombus, or ischemic myocardial infarction occurred. Histologic extent of thermal injury in treated segments was proportional to treatment duration. Thus the thermal-perfusion balloon angioplasty system may be safely applied in canine coronary arteries. Integrating thermal and perfusion technologies provides prolonged treatment duration at moderate temperatures without excessive tissue damage.

PTCA with side-by-side balloon using fixed guide wire systems: a potential alternative autoperfusion device--an in vitro study

The use of "hugging balloons" for the implementation of a coronary angioplasty is a well-known and much-written-about technique. It has not, on the other hand, ever been stressed that two inflated hugging balloons are not totally obstructive, leaving enough space, between the balloons and the arterial wall, for perfusion. The cross section of this free area can be as much as 12% of the total arterial cross section, when the side-by-side balloons are of a relatively similar size. Calculations show that similar total conduit cross sections are achieved when inflating either a 3.0 balloon or two 2.0 side-by-side balloons. An in vitro experiment compares how systems using 2.0 double balloons and a 3.0 autoperfusion balloon affect the distal flow of a 3 mm internal diameter conduit. A semi-rigid silastic tubing is perfused with a 5% glucose isotonic solution at various predetermined proximal pressure levels. Distal pressures and flows are measured at different stages: with no balloon, with deflated balloons, and with inflated balloons. Comparison shows that 1) the double balloon system offers little resistance to flow compared to the autoperfusion balloon; 2) this system's rate of perfusion run-off is hardly affected and is constantly better than with the autoperfusion balloon; 3) this difference is all the more marked, the lower the proximal perfusion. These results suggest that the use of a double balloon could, in some cases, provide an alternative solution to autoperfusion equipment. Further clinical studies are needed to test this hypothesis.

Protection against ischemia during prolonged balloon inflation by distal coronary perfusion with use of an autoperfusion catheter or Fluosol

OBJECTIVES

The purpose of this report was to study the protective effects of passive and active distal coronary perfusion during prolonged balloon inflation.

BACKGROUND

Prolonged balloon inflation has been proposed to improve immediate and long-term results of percutaneous transluminal coronary angioplasty, but it requires protection against myocardial ischemia.

METHODS

A 30-min balloon occlusion of the left anterior descending artery was performed in three groups of closed chest anesthetized dogs: 1) control (no distal coronary perfusion, n = 13), 2) passive distal coronary perfusion (autoperfusion catheter, n = 10), and 3) active distal coronary perfusion (infusion of the perfluorochemical Fluosol at 30 ml/min, n = 11).

RESULTS

At 10 min of balloon inflation, echocardiographic wall motion indexes (scored from 1 [normal] to 5 [dyskinesia]) in the autoperfusion catheter and Fluosol groups (2.4 +/- 1.2 and 2.0 +/- 0.9, respectively) were significantly better than in the control group (3.6 +/- 0.4, p = 0.001), but at 25 min this improvement in wall motion had attenuated and became statistically insignificant when compared with values in the control group. Left ventricular end-diastolic pressure at peak inflation in the Fluosol group (19.5 +/- 5.5 mm Hg) was higher than in the control (7.6 +/- 3.6) and autoperfusion catheter (5.3 +/- 1.4, p < or = 0.01) groups. Pathologic evidence of infarction by tetrazolium staining was seen in three control dogs and in none of the other groups (p = 0.07). Ventricular tachycardia and fibrillation were less frequent in the autoperfusion catheter group (p = 0.02). Three deaths were observed in the control dogs, two in the Fluosol group and none in the dogs with an autoperfusion catheter (p = NS).

CONCLUSIONS

Passive (the autoperfusion balloon catheter) and active (Fluosol) distal coronary perfusion methods are comparable and better than no perfusion in protecting the myocardium against ischemia produced by prolonged coronary balloon inflation in an experimental canine model. This protection is transient, attenuating after 10 to 25 min, and partial because there was no significant difference in the incidence of myocardial infarction and death among groups, although the latter observations may be related to small sample size.

Aggressive clinical pattern of angina at restenosis following coronary angioplasty in unstable angina

The frequency, clinical pattern, and timing of recurrent angina following successful single-lesion percutaneous transluminal coronary angioplasty (PTCA) was assessed in a consecutive group of 104 patients with stable angina and in 85 with unstable angina. In addition, the relationship between lesion morphology and angiographic features and the pattern of recurrent angina was determined. Restenosis, defined as recurrence of symptoms with > 50% stenosis at the site of PTCA, occurred in 25 (24%) of the stable group and in 23 (27%) of the unstable group (p = NS). The pattern of angina at repeat presentation was aggressive in nature in 8% of the stable group and in 48% of the unstable group (p = 0.002). The time interval between the recurrence of symptoms and repeat coronary angiogram or PTCA was longer in the nonaggressive group than in the aggressive group, 16 +/- 12.1 and 5 +/- 6.8 weeks, respectively (p < 0.003). The key factors predicting the recurrent angina pattern identified by multiple logistic regression analysis were the angina status pre-PTCA (p = 0.001) and the presence of double-vessel disease (p = 0.01). An aggressive pattern of angina at the time of restenosis is frequent in patients with unstable angina at the time of PTCA, and close post-PTCA surveillance is necessary in these patients.

Excimer laser ablation before autoperfusion balloon inflation: a novel therapeutic approach to high grade stenoses in vessels supplying substantial myocardium at risk

The utility of a novel approach employing excimer laser ablation to form a channel for subsequent autoperfusion balloon angioplasty is presented. Two important advantages of this strategy are highlighted: (1) applicability to severe stenoses in vessels supplying substantial myocardium at risk and (2) ability to allow prolonged inflation time to minimize procedure related ischemia and optimize revascularization of the heart. We prospectively selected and studied five patients and performed excimer laser coronary angioplasty using either a 1.3 mm or 1.6 mm laser catheter followed by autoperfusion balloon dilatation. Procedural success was documented by a significant reduction in mean percent diameter stenosis from 89 +/- 4% (S.D.) to 53 +/- 4% after laser angioplasty (p < 0.0001) and subsequently to 20 +/- 4% after autoperfusion balloon angioplasty (p < 0.0001). Clinical success was attained and characterized by resolution of anginal symptoms for at least 4 weeks after hospital discharge. There were no major acute complications encountered; however, restenosis has occurred in 2 out of 5 patients. We therefore recommend this novel pre-dilation strategy with excimer laser followed by autoperfusion balloon angioplasty in selected patients with an extensive amount of myocardium at risk.

Myocardial revascularization. Coronary angioplasty and bypass surgery indications

Coronary artery bypass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA) have been performed increasingly over the last 20 and 10 years, respectively. The growth in PTCA is both complementary and threatening to CABG. The controversy between cardiologists and cardiac surgeons over the role of each procedure will no doubt continue as new devices are developed for coronary interventions. This article reviews the controversy and provides information to internists so that they will be fully prepared to advise patients about their treatment options.

Prospective analysis of possible myocardial damage or hemolysis occurring as a result of prolonged autoperfusion angioplasty in humans

OBJECTIVES

The purpose of this study was to further explore the procedural safety of prolonged (15-min) dilation using an autoperfusion coronary angioplasty balloon by assessing the degree of myocardial damage or hemolysis, if any, occurring as a result of the procedure.

BACKGROUND

Prolonged balloon inflation periods may be beneficial during percutaneous transluminal coronary angioplasty. The duration of standard balloon angioplasty is often limited by the occurrence of myocardial ischemia due to loss of anterograde blood flow. Autoperfusion angioplasty allows continued myocardial perfusion during balloon inflation and has previously been shown to reduce but not totally eliminate acute myocardial ischemia during prolonged (up to 15 min) balloon inflation. The risk of intravascular hemolysis as a result of autoperfusion angioplasty has not yet been fully delineated.

METHODS

Sixty-two consecutive patients (76% men; mean age 58 years) undergoing elective percutaneous transluminal coronary angioplasty of a single lesion were studied. Serial electrocardiographic and creatine kinase MB isoenzyme data were examined to detect evidence of myocardial damage. Tests for hemolysis (plasma free hemoglobin, serum haptoglobin and serum lactate dehydrogenase) were obtained in the 1st 24 consecutive patients.

RESULTS

Inflation time was 14 +/- 4 min (mean +/- SD) and the procedure was successful (less than or equal to 50% residual lesion stenosis) in 59 patients (95%). Electrocardiographic evidence of myocardial infarction (greater than 1 mm persistent ST segment depression, greater than 1 mm ST segment elevation or new Q waves) was not observed in any patient. Cardiac enzyme assays were within the normal range in all patients. No evidence of hemolysis was found in the 24 consecutive patients studied.

CONCLUSIONS

We conclude that prolonged autoperfusion angioplasty can be performed in patients without clinical evidence of myocardial damage or hemolysis.

Coronary angioplasty performed with gradual and prolonged inflation using a perfusion balloon catheter: procedural success and restenosis rate

The results of routine coronary angioplasty using gradual and prolonged balloon inflation with a perfusion balloon catheter were evaluated. One hundred forty patients were treated with inflation of the balloon to 6 atm over 3 minutes, with a median inflation time of 15 minutes. The procedural success rate (residual stenosis less than or equal to 50%) was 99%. In-hospital major complications occurred in five patients (3.6%), with one patient experiencing a periprocedural infarction, three patients requiring bypass surgery for abrupt closure, and one patient dying after elective bypass surgery following previous successful angioplasty of a culprit lesion. The restenosis rate in the 117 patients with angiographic follow-up (87% of those eligible) was 42%. Thus gradual and prolonged inflation using a perfusion balloon catheter resulted in a high procedural success rate and a restenosis rate similar to that reported in large studies of patients treated with standard angioplasty. These results warrant further study using a prospective randomized trial design.

ACS RX flow support catheter as a temporary stent for dissection or occlusion during balloon angioplasty: initial experience

The ACS RX flow support catheter, which functions as a temporary stent, was placed successfully during four procedures in three patients who had suboptimal results following angioplasty. This investigational device allowed prolonged perfusion and supported the vessel wall when coronary blood flow was compromised, avoiding emergent coronary artery bypass graft surgery during two procedures. In the remaining procedures the device was used as a bridge to surgery. These early applications of the flow support catheter following failed balloon angioplasty suggest a rapid, effective alternative to the autoperfusion balloon when it fails or is contraindicated because of the lesion location.

Use of an autoperfusion catheter in the treatment of acute refractory vessel closure after coronary balloon angioplasty: immediate and six month follow up results

OBJECTIVE

To determine the usefulness of the Stack autopersion dilatation catheter in patients with acute recurrent vessel closure during coronary angioplasty.

DESIGN

Prospective data collection.

SETTING

University hospital.

PATIENTS

In 37 of 1003 consecutive patients undergoing angioplasty between November 1989 and December 1990 acute vessel closure developed that could not be redilated by a conventional balloon catheter. 13 (35%) of these 37 patients were sent immediately for emergency bypass surgery.

INTERVENTION

In the remaining 24 patients an attempt was made to reopen the vessel with a Stack catheter.

MAIN OUTCOME MEASURE

Successful reopening of the vessel. All successfully treated patients were followed for at least six months to detect recurrent ischaemia.

RESULTS

In 16 patients (67%) the Stack procedure was successful. Of the eight patients in whom reopening of the occluded vessel was not achieved, seven were sent for bypass surgery and one was successfully treated by emergency stent implantation. The 16 patients successfully treated with the Stack autoperfusion system were followed up for a mean (SD) of 6.7 (2.6) (range 2 to 11) months. Ten patients remained symptom free but early clinical restenosis developed in four (25%). Overall, only three (19%) of 16 patients experienced recurrence of severe (class III-IV) symptoms and required further mechanical revascularisation.

CONCLUSION

These data support the use of the Stack autoperfusion catheter system in selected patients with acute vessel closure not responsive to attempted redilatation with conventional balloon catheters. The short-term outcome seen in this series of patients who were successfully treated with this coronary autoperfusion system is encouraging.

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

Prolonged balloon inflation with or without autoperfusion techniques is a common initial approach to major dissection or abrupt occlusion after percutaneous transluminal coronary angioplasty (PTCA). To assess such a strategy in the setting of unsuccessful angioplasty, 40 patients who underwent prolonged balloon inflations of greater than 20 minutes between January and July of 1991 after initially unsuccessful angioplasty were studied. These patients (median age 59 years) underwent PTCA for progressive or unstable angina (16[40%]), symptomatic or asymptomatic residual stenosis after myocardial infarction (10[25%]), acute myocardial infarction (3[8%]), stable angina (3[8%]), reinfarction (2[5%]), and other indications (6[15%]). The significant stenoses were primarily in the proximal and midportions of the right coronary (53%), left anterior descending (30%) and left circumflex (17%) coronary arteries. Before prolonged balloon inflation, the longest single inflation was 11 +/- 6 minutes and the total time of all inflations was 17 +/- 8 minutes (mean +/- standard deviation). Stenosis was reduced from 91 +/- 9 to 68 +/- 16% before prolonged inflation. After prolonged balloon inflation of 30 +/- 9 minutes, the residual stenosis was 47 +/- 21% (p = 0.0001 vs value before prolonged inflation). Furthermore, improvements in the appearance of filling defects or dissections, or both, occurred in 19 patients (48%). Procedural success was obtained in 32 of 40 patients (80%). Coronary bypass grafting was performed in 8 patients (20%): 4 after unsuccessful PTCA (3 emergently) and 4 electively after initially successful PTCA. Although 5 patients had creatine kinase-MB elevations greater than 20 IU/liter after the procedure, only 1 sustained a Q-wave myocardial infarction. There were no deaths in the hospital.(ABSTRACT TRUNCATED AT 250 WORDS)