New balloon catheter for prolonged percutaneous transluminal coronary angioplasty and bypass flow in occluded vessels

Aortic dissection with concomitant acute myocardial infarction: From diagnosis to management

Acute aortic dissection an extremely severe condition having a high risk of mortality. The classic symptom may mimic other conditions such as myocardial ischemia, leading to misdiagnosis. Coronary malperfusion associated with aortic dissection is relatively rare, but when it occurs, it may have a fatal result for the patient. The diagnosis of acute coronary syndrome may lead to the inappropriate administration of thrombolytic or anticoagulant treatment resulting in catastrophic consequences. Emergency imaging techniques help to guide the correct diagnosis. Transthoracic echocardiography is useful as a first imaging test, and may be followed by transesophageal echocardiography, or other imaging techniques. Surgery represents the treatment for these patients. However, with the aim to stabilize the patient and to reduce myocardial damage, initial preoperative endovascular coronary intervention has been reported.

Acute and long-term outcome after coronary artery perforation during percutaneous coronary interventions

BACKGROUND

Coronary artery perforation is a rare but serious complication of percutaneous coronary interventions (PCI).

METHODS

We reviewed our database for cases of overt coronary perforation during PCI procedures. Hospital charts, procedural reports, and coronary angiograms of these patients were reviewed, with particular emphasis on mechanisms of perforation, management of the complication, and clinical outcome.

RESULTS

Between 01/1998 and 12/2003, a total of 19 cases (mean age: 66+/-8 years, 13 male) of coronary perforation occurred during 6433 PCI procedures performed within this period (incidence: 0.3%). In 12/19 (63%) cases, perforation occurred during recanalisation procedures of chronic total occlusions of coronary arteries. In all but one patient, non-surgical management was attempted: 2 out of 19 (11%) patients were treated conservatively by reversal of heparin anticoagulation. Prolonged balloon inflation at the perforation site was applied in 10/19 (53%) patients. Six (32%) patients received stents (5 of them received covered stentgrafts), 3 (16%) patients developed cardiac tamponade requiring percardiocentesis, and only 2 (11%) patients underwent bailout surgical repair. There were 2 (11%) deaths early after the procedure.

CONCLUSION

Coronary perforation during PCI is a rare complication, but is associated with significant morbidity and mortality. In the majority of patients, non-surgical management is both feasible and associated with a high success-rate.

Use of intracoronary electrocardiography for detecting ST-T, QTc, and U wave changes during coronary balloon angioplasty

Intracoronary electrocardiography (IC-ECG) is a more sensitive method than surface ECG to detect electrical changes during percutaneous transluminal coronary angioplasty (PTCA). It also provides direct monitoring of ST-T segment, QTc intervals, and U-wave genesis during balloon inflation. These changes are reflective of myocardial ischemia. The authors studied the effect of transient myocardial ischemia on ST-T segment, QTc intervals, and U-wave appearance by comparing standard and perfusion balloon angioplasty. PTCA of left anterior descending artery was performed in 14 patients using the standard balloons and in 11 patients using the perfusion balloons. Patients with perfusion balloon angioplasty had less ST-T elevation (0.15 +/- 0.05 mV versus 1.04 +/- 0.19 mV, P < 0.001), less QTc-shortening intervals (0.01 +/- 0.02 seconds versus -0.05 +/- 0.04 seconds, P < 0.001), and less positive U waves (two versus nine). The authors concluded that balloon angioplasty with perfusion balloons is associated with less ischemia as reflected by ST-T, QTc-shortening intervals, and U-wave changes. There was more positive U-wave appearance with the standard balloon angioplasty, which implies more ischemia. In addition, QTc-shortening intervals are associated with the development of U waves during standard balloon angioplasty. These findings suggest that IC-ECG is a sensitive tool in detecting myocardial ischemia. IC-ECG may also help to clarify the nature of chest pain during PTCA in some patients. Like QT dispersion (QTd), QTc-shortening intervals and new U waves can have prognostic implications and additional studies are needed to define this role.

Immediate stent implantation versus conventional techniques for the treatment of abrupt vessel closure or symptomatic dissections after coronary balloon angioplasty

BACKGROUND

Coronary stenting was initially designed to treat a bailout scenario. Prospective randomized trials comparing stent implantation with standard techniques, including emergency coronary artery bypass grafting, are lacking. The aim of this trial was to test the superiority of immediate stent implantation compared with standard techniques for the treatment of abrupt or threatening closure after coronary balloon angioplasty.

METHODS

In a prospective trial, 100 patients with abrupt vessel closure or symptomatic dissections causing objective signs of ischemia were randomly assigned to treatment with immediate placement of stents (n = 51) versus standard techniques such as prolonged dilatation or emergency bypass surgery (n = 49). The primary end point was the achievement of successful stabilization not requiring crossover to the other study group. Secondary end points included event-free survival and restenosis.

RESULTS

Successful stabilization was achieved in 94% of patients in the stent group compared with 78% of patients in the standard treatment group (P =.038). Two patients died in each group, and there was a trend toward a higher incidence of myocardial infarction (16% vs 8%; P =.163) and a significantly increased creatine phosphokinase level (245 IU/L [95% confidence interval, 217-265 IU/L] vs 179 IU/L [confidence interval 140-212 IU/L]; P =.0002) in the standard treatment group. Event-free survival after 250 days was 72% in the stent group compared with 29% in the standard treatment group (P =.001). The angiographic restenosis rate was 30% in the stent group versus 59% in the standard treatment group (P =.01).

CONCLUSIONS

Immediate stenting, if technically feasible, shows superior short- and long-term results compared with standard treatment options.

High-resolution intravascular magnetic resonance imaging: monitoring of plaque formation in heritable hyperlipidemic rabbits

BACKGROUND

The individual makeup of atherosclerotic plaque has been identified as a dominant prognostic factor. With the use of an intravascular magnetic resonance (MR) catheter coil, we evaluated the effectiveness of high-resolution MR in the study of the development of atherosclerotic lesions in heritable hyperlipidemic rabbits.

METHODS AND RESULTS

Sixteen hyperlipidemic rabbits were investigated at the ages of 6, 12, 24, and 36 months. The aorta was studied with digital subtraction angiography and high-resolution MR with the use of a surface coil and an intravascular coil that consisted of a single-loop copper wire integrated in a 5F balloon catheter. Images were correlated with histological sections regarding wall thickness, plaque area, and plaque components. Digital subtraction angiography revealed no abnormalities in the 6- and 12-month-old rabbits and only mild stenoses in the 24- and 36-month-old rabbits. High-resolution imaging with surface coils resulted in an in-plane resolution of 234x468 microm. Delineation of the vessel wall was not possible in younger rabbits and correlated only poorly with microscopic measurements in the 36-month-old rabbits. Intravascular images achieved an in-plane resolution of 117x156 microm. Increasing thickness of the aortic wall and plaque area was observed with increasing age. In the 24- and 36-month-old animals, calcification could be differentiated from fibrous and fatty tissue on the basis of the T2-fast spin echo images, as confirmed by histological correlation.

CONCLUSIONS

Atherosclerotic evolution of hyperlipidemic rabbits can be monitored with high-resolution intravascular MR imaging. Image quality is sufficient to determine wall thickness and plaque area and to differentiate plaque components.

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.

ST-T alternans and myocardial ischemia

Previous studies using intracoronary electrocardiography have demonstrated that ST-T alternans can develop during standard balloon coronary angioplasty. Total occlusion with a large amount of myocardium in jeopardy is the postulated prerequisite. In this study, the authors used perfusion balloons instead of standard balloons, so coronary perfusion was maintained and ischemia was minimized. Fourteen patients with standard balloon technique and 11 patients with perfusion balloon technique were studied. The ST segment was less elevated during perfusion angioplasty (0.15 +/- 0.05 mV vs 1.04 +/- 0.19 mV, p<0.001). There were six (43%) patients with ST-T alternans with standard balloon technique compared with none in the perfusion balloon group (p<0.001). In this study, the authors found that there was less ischemia, less ST segment elevation, and lack of ST-T alternans on the intracoronary electrocardiogram during perfusion balloon angioplasty. These findings support the postulate that a large amount of ischemic myocardium is a prerequisite for ST-T alternans.

Tissue Doppler echocardiography: a new method of evaluating perfusion-dependent myocardial function during PTCA

The increasing demand for insight into the relationship between coronary perfusion and myocardial function stimulated the development of tissue Doppler echocardiography. This new technique was applied simultaneously with PTCA of a subtotal LAD lesion (single vessel disease, no collaterals) in a 68-year-old patient suffering from unstable angina pectoris. Prior to the conventional signs of ischaemia a decrease in myocardial tissue velocities and a loss of color-coded heart cycle intervals was observed. A myocardial velocity gradient calculated from the higher subendocardial and lower subepicardial velocity decreased from 3.3 to 1.3. This decrease was prevented by an active autohaemoperfusion device which supplied blood distally to an insufflated balloon (60 ml/min). Thus, contractility and viability might be maintained by preserving myocardial velocity gradients.

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.

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.

Coronary artery and saphenous vein graft remodeling: a review of histologic findings after various interventional procedures--Part II

Catheter balloon angioplasty is a well accepted form of nonsurgical treatment of acutely and chronically obstructed coronary artery vessels. It is also the centerpiece for various new intervention techniques. Their morphologic effects on the site of obstruction has been termed "remodeling." Part II of this six-part series focuses on morphologic causes of acute closure after remodeling and discusses findings late after successful balloon angioplasty remodeling.

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.

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.

Regional flow adjusted hemoperfusion during coronary angioplasty: circulatory support/myocardial protection

Routine percutaneous transluminal coronary angioplasty catheters are adequate and demonstrate high success rates in balloon angioplasty with stable patients. Active hemoperfusion seems to offer an advantage in patients with hemodynamic instability. Active hemoperfusion provides myocardial protection during coronary interventions and can be applied in conjunction with routine angioplasty equipment. When compared with other devices demonstrating clinical utility in a supported angioplasty setting, this flow adjustable active antegrade hemoperfusion pump appears reliable, simple to use, cost-effective, and requires much less instrumentation than the more bulky CPS systems.

The history of interventional cardiology: cardiac catheterization, angioplasty, and related interventions

The histories of cardiac catheterization, angioplasty, and other catheter interventions are spectacular journeys marked by undeterred genius, serendipity, and the vindication of the scientific method. Cardiac catheterization began with Hales's 1711 equine biventricular catheterization, other early experimental catheterizations in the nineteenth century, and Forssmann's dramatic 1929 right-heart self-catheterization. Cournand, Richards, and others finished unlocking the right heart in the 1940s; Zimmerman, Cope, Ross, and others unlocked the left heart in the 1950s; and the coronary arteries were inadvertently unlocked by Sones in 1958, leading to the advent of percutaneous femoral coronary angiography by Judkins and by Amplatz in 1967. Dotter's accidental catheter recanalization of a peripheral artery in 1963 ushered in the era of intervention, crowned by Gruentzig's balloon angioplasty in the mid-1970s and leading to today's panoply of devices used percutaneously to revascularize the coronary arteries in a variety of clinical settings.

Prolonged dilation with an autoperfusion balloon catheter for refractory acute occlusion related to percutaneous transluminal coronary angioplasty

OBJECTIVES

Efficacy and safety of redilation by an autoperfusion balloon catheter over several hours were investigated in this retrospective and observational study.

BACKGROUND

Acute occlusion, refractory to redilation, is a serious complication of coronary angioplasty.

METHODS

Of 1,123 patients who underwent angioplasty, 83 had a refractory acute occlusion. Thiry-five patients were treated with extended dilation. Seven had stable, 19 unstable and 6 postinfarction angina and 3 had an acute infarction at the time of angioplasty. The duration of dilation was (mean +/- SD) 17 (+/- 6) h.

RESULTS

Angiographically successful redilation, with a mean residual percent diameter stenosis of 13.5% (+/- 11.6%), was achieved in 22 (67.7%) of 34 patients. Five patients underwent bypass surgery. Three patients, who were poor surgical candidates, died. There was one new Q wave infarction and one death that occurred during extended dilation; one death and four operations were related to reocclusion immediately (< or = 30 min) after catheter withdrawal; and one death and one operation were related to in-hospital reocclusion. Overall success, defined as angiographic success and freedom from major events, was obtained in 20 (57%) of 35 patients (95% confidence interval 41% to 73%). Of the variables studied, only multilesion dilation was significantly (p = 0.018) associated with an unfavorable outcome. During a mean follow-up period of 13.8 (+/- 6.1) months, two patients underwent repeat angioplasty, one sustained an infarction and three underwent elective bypass surgery.

CONCLUSIONS

In approximately half of the patients (20 [57%] of 35), an initial angioplasty failure due to refractory occlusion could be reverted to a successful procedure by prolonged dilation with an autoperfusion balloon catheter.

In vitro evaluation of blood flow through autoperfusion balloon catheters

The effective flow rates with human blood through an autoperfusion catheter cannot be monitored in vivo and have not been experimentally determined in vitro. The manufacturers (Advanced Cardiovascular Systems [ACS], Temecula, CA) have suggested that "the flow rate" through the Stack over the wire and the RX-60 monorail catheter is 60 ml/min with a pressure gradient of 80 mmHg. We measured human blood flow rates in vitro through these catheters under different continuous pressure regimens (between 40 and 120 mmHg), with varying hematocrit levels (between 25% and 62%). Measured blood flows at a gradient of 80 mmHg were found to vary from 32 to 65 cc/min, with hematocrit levels of 62-25%. Minor variations in the circuitry, besides the viscosity of the medium, cause significant changes in observed flow rates (such as kinking of the catheter and blood sedimentation). In vitro determinations of blood flows cannot automatically be transferred to the in vivo condition, primarily because in vitro determinations do not account for the systolic intramural pressure increase (which may overcome the aortic pressure). If such a phenomenon is also considered, then the in vitro flow rates reported here should be multiplied by a factor of 0.40-0.60 to determine effective in vivo flow rates. Such information is relevant for the clinical operator of angioplasty, especially in the treatment of patients at high risk for undergoing percutaneous transluminal coronary angioplasty.

Success with coronary angioplasty as seen at demonstrations of procedure

To assess the real-life results of coronary angioplasty, unidentified participants made notes on 104 cases demonstrated live at twelve international angioplasty courses in 1991. The initially planned procedure was successful in 73% with crossover to another device in 20% for an ultimate success rate of 93%. Interventions lasted an hour on average and two devices on average were used per artery tackled. Rates of success and of complication necessitating reintervention were, for balloon angioplasty (57 cases) 81% and 19%, for directional atherectomy (16 cases) 75% and 0%, for the Rotablator (12 cases) 42% and 42%, for stent implantation (10 cases) 100% and 0%, for excimer laser angioplasty (6 cases) 17% and 33%, and for Rotacs recanalisation (3 cases) 67% and 0%, respectively. The complications were occlusions (threatened, acute, or delayed) and they were usually treated by balloon angioplasty or a stent. No death or myocardial infarction was reported. The observer attending the demonstration tended to take a less favourable view of the outcome than the clinician doing the procedure and in general the results of coronary angioplasty seemed inferior to those reported in journals. Interventions done before an audience will be unusually stressful but this will be outweighed by the fact that difficult cases with a low probability of success are rarely tackled during live courses. This survey suggests that conventional balloon angioplasty, complemented by stent implantation in selected cases, is the treatment of choice.

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.

Design and testing of a high-flow autoperfusion catheter: an experimental study

An autoperfusion catheter is similar to an angioplasty balloon catheter with side holes in the guide-wire lumen proximal to the balloon. When the balloon of the autoperfusion catheter is deployed and inflated in an artery, the guide wire is removed, and the hub of the guide-wire lumen is capped. The catheter then allows passive distal perfusion by using ambient pressure to drive blood into the guide-wire lumen, through the balloon, and out the end hole. This article discusses the requirements and constraints of a high-flow autoperfusion catheter, summarizes attempts to modify standard angioplasty catheters for use as an autoperfusion catheter, and describes the design and testing of a custom autoperfusion catheter capable of delivering approximately 3 mL/sec at physiologic pressures. In a model of canine acute renal artery occlusion lasting 90 minutes, the custom autoperfusion catheter provided marked protection from acute tubular necrosis compared with conventional percutaneous transluminal angioplasty catheters. The authors conclude that the high-flow autoperfusion catheter may be useful as a temporary stent in cases of rupture, dissection, or penetrating wounds involving large arteries.

Effects of hemoperfusion during percutaneous transluminal coronary angioplasty on left ventricular function

The effect of autologous blood perfusion, delivered through an angiographic power injector, on alleviating left ventricular (LV) hemodynamic deterioration during percutaneous transluminal coronary angioplasty (PTCA) was examined. LV systolic and diastolic pressures, LV peak positive and peak negative first derivative of LV pressure (dP/dt), and ST-segment shift were recorded in 9 patients with and without hemoperfusion. Hemoperfusion resulted in an improved LV hemodynamic profile during balloon occlusion, as reflected in LV systolic pressure (127 +/- 14 vs 120 +/- 15 mm Hg, p = 0.01), LV end-diastolic pressure (17 +/- 14 vs 25 +/- 6 mm Hg, p less than 0.001), peak positive (1,237 +/- 240 vs 1,149 +/- 225 mm Hg/s, p less than 0.05) and peak negative (1,666 +/- 357 vs 1,485 +/- 385 mm Hg/s, p = 0.003) dP/dt. Hemoperfusion provides substantial protection for significant LV dysfunction induced by conventional PTCA in 1-vessel angioplasty and is a feasible option to protect against potential cardiovascular collapse in high-risk PTCA.

Percutaneous support devices for high risk or complicated coronary angioplasty

Indications for coronary angioplasty have expanded to include patients with unstable acute ischemic syndromes, severe multivessel coronary artery disease and impaired left ventricular function. Several mechanical approaches have been developed as adjuncts to high risk coronary angioplasty to improve patient tolerance of coronary balloon occlusion and maintain hemodynamic stability in the event of complications. These percutaneous techniques include intraaortic balloon counterpulsation, anterograde transcatheter coronary perfusion, coronary sinus retroperfusion, cardiopulmonary bypass, Hemopump left ventricular assistance and partial left heart bypass. The intraaortic balloon pump provides hemodynamic support and ameliorates ischemia by decreasing myocardial work; it may be inserted for periprocedural complications or before angioplasty in patients with ischemia or hypotension. Anterograde distal coronary artery perfusion may be accomplished passively through an autoperfusion catheter or by active pumping of oxygenated blood or fluorocarbons through the central lumen of an angioplasty catheter. Synchronized coronary sinus retroperfusion produces pulsatile blood flow via the cardiac veins to the coronary bed distal to a stenosis. Both perfusion techniques limit development of ischemic chest pain and myocardial dysfunction in patients undergoing prolonged balloon inflations. Percutaneous cardiopulmonary bypass provides complete systemic hemodynamic support which is independent of intrinsic cardiac function or rhythm and has been employed prophylactically in very high risk patients before coronary angioplasty or emergently for abrupt closure. These and newer 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.

Preservation of regional myocardial function during coronary angioplasty with an autoperfusion balloon catheter: a case report

Echocardiographic assessment of regional myocardial function was performed during standard balloon coronary angioplasty followed by autoperfusion balloon angioplasty of a proximal left anterior descending artery stenosis. Septal and apical akinesis occurred within 60 seconds of standard balloon inflation, but regional function was well preserved during prolonged autoperfusion balloon inflation.

Experience with the use of coronary autoperfusion catheter during complicated angioplasty

Between February and July of 1989, 22 patients underwent the use of the Stack autoperfusion catheter following acute occlusion or obstructive dissection during coronary angioplasty; in 20 cases conventional balloon was used in an attempt to correct the angiographic appearance followed by the use of Stack catheter when results were sub-optimal. Only 1 patient (4.5%) required surgical revascularization. Although our study is not prospective or randomized, our observations suggest a significant impact in decreasing the need for emergency surgical revascularization after complicated coronary angioplasty with the use of this approach.

New passive perfusion PTCA catheter

Percutaneous coronary angioplasty with a new passive perfusion balloon catheter was compared to a standard angioplasty balloon catheter during prolonged balloon inflations in miniature swine. Inflations with the passive perfusion balloon were alternated with a standard balloon with the initial balloon chosen randomly in 24 coronary arteries. End-points for terminating the balloon inflation were the appearance of 2 mm of ST segment deviation from baseline on the electrocardiogram, the occurrence of ventricular fibrillation, or 30 min of balloon inflation. During balloon inflation contrast injections were performed through the guiding catheter and flow distal to the balloon was graded 0-3 using the TIMI scale. The average (+/- SD) inflation time for the standard balloon was 3.1 +/- 2.2 minutes and for the perfusion balloon was 27.2 +/- 4.8 min (P less than 0.001). Electrocardiographic evidence of 2 mm of ST segment deviation from baseline was seen during 11/13 inflations with the standard balloon and in 3/11 balloon inflations with the perfusion balloon. Ventricular fibrillation occurred during 2/13 of the standard balloon inflations and in none during passive balloon inflations. Distal contrast flow during passive balloon inflations averaged 2.7 +/- 0.5 (TIMI scale 0-3) and was absent during inflations with the standard balloon. The perfusion balloon allowed prolonged inflations with excellent distal flow when compared to the standard balloon.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional myocardial blood flow with a reperfusion catheter and an autoperfusion balloon catheter during total coronary occlusion

We investigated the ability of two new coronary perfusion catheters to maintain regional myocardial blood flow throughout a 90-minute period of occlusion. In 21 dogs (group I = total occlusion control; group II = reperfusion catheter; group III = autoperfusion balloon catheter) we studied regional blood flow, distal coronary perfusion pressure, infarct size, and red blood cell hemolysis after placement of either catheter into the left anterior descending coronary artery. Regional (microsphere) blood flow showed a reduction in transmural blood flow during occlusion in comparison to baseline values (1.07 +/- 0.12 to 0.81 +/- 0.11 and 1.01 +/- 0.16 to 0.73 +/- 0.08 ml/min subendocardial perfusion for groups II and III, respectively). Comparable changes in blood flow were observed in the subepicardial and midmyocardial regions. Distal coronary perfusion pressures were reduced by 26% and 28% for groups II and III, respectively. Both catheters prevented significant infarction and maintained adequate regional myocardial blood flow throughout the 90-minute period of occlusion without significant complications of clotting or destruction of erythrocytes.

"Crackers, breakers, stretchers, drillers, scrapers, shavers, burners, welders and melters"--the future treatment of atherosclerotic coronary artery disease? A clinical-morphologic assessment

Although various public health preventive efforts and prescribed pharmacologic treatment methods will have long-term benefits in the reduction of coronary artery atherosclerosis and subsequent cardiac events, the immediate and short-term future in the treatment of coronary artery disease will focus on several interventional devices designed to remodel or remove causes of acute and chronic coronary artery obstruction. Certain clinical-morphologic aspects of these interventional devices or techniques that result in remodeling of the coronary lumen shape (balloon angioplasty, thermal probes, intravascular stents) or removal of obstructing material (lasers, atherectomy devices) are reviewed. Two new areas in the pathology of atherosclerotic plaque (plaque fissures, eccentric plaque) and their clinical relevance in coronary heart disease are described.

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

An autoperfusion balloon catheter was developed to allow passive myocardial perfusion during inflation through a central lumen and multiple side holes in the shaft proximal and distal to the balloon. We report its safety and efficacy in 11 patients undergoing elective angioplasty to a single coronary lesion. Each lesion was dilated three times with the autoperfusion inflation bracketed between two inflations by standard angioplasty catheters. Chest pain score, 12-lead electrocardiogram, heart rate, and mean aortic pressure were recorded before each inflation and at 1-minute intervals after inflation. Inflation duration during autoperfusion angioplasty (513 +/- 303 seconds) was longer than for the pre- (107 +/- 55 seconds, p = 0.0004) and post- (139 +/- 71 seconds, p = 0.0006) standard dilatations. The maximum ST-segment elevation and depression in any lead during autoperfusion angioplasty (0.3 +/- 0.5 and 0.6 +/- 0.8 mm) was significantly less than for the pre- (2.4 +/- 1.7 mm, p = 0.002 and 2.2 +/- 1.3 mm, p = 0.0004) or post- (1.9 +/- 1.3 mm, p = 0.002 and 1.6 +/- 1.3 mm, p = 0.018) standard dilatations at the same point in time. Maximal chest pain score during autoperfusion (3.2 +/- 3.5) was lower than for the pre- (6.1 +/- 2.1, p = 0.003) but not the post- (5.2 +/- 3.1, p = 0.07) standard angioplasty. All 11 patients underwent successful, uncomplicated procedures. We conclude that this autoperfusion catheter significantly reduces ischemic symptoms and signs during coronary angioplasty, allowing prolonged periods of balloon inflation.

Amelioration of ischemia during angioplasty of the left anterior descending coronary artery with an autoperfusion catheter

A new autoperfusion balloon angioplasty catheter with sideholes proximal and distal to the balloon--facilitating distal blood flow during inflation--was compared with standard angioplasty catheters in a prospective, randomized study with blinded data analysis. Hemodynamic and electrocardiographic markers of ischemia after 1 minute of standard or autoperfusion catheter inflations were compared with ischemia after control inflation with standard balloons. In the patient group randomized to standard balloon inflation only, ST-segment elevation after control inflation with a standard balloon catheter was 0.37 +/- 0.04 mV; ST-segment elevation after final balloon inflation with a standard catheter was unchanged at 0.35 +/- 0.04 mV (difference not significant). In the group randomized to the autoperfusion catheter, control inflation with a standard catheter resulted in 0.48 +/- 0.1 mV ST elevation; final inflation with the autoperfusion catheter demonstrated 0.16 +/- 0.09 mV ST elevation (p less than 0.005). Autoperfusion catheter inflation was continued for 2 minutes without change in electrocardiographic findings: ST segments remained at 0.08 +/- 0.03 mV, unchanged from 0.07 +/- 0.03 mV before angioplasty (difference not significant). Thus, while coronary angioplasty performed with standard catheters resulted in marked ST-segment elevation, in patients undergoing angioplasty with the autoperfusion catheter, ischemia was generally not seen, despite sustained balloon inflation for 2 minutes.

Perfusion balloon catheter

An autoperfusion balloon catheter was developed to allow passive myocardial perfusion during balloon inflation, through a central lumen and multiple side holes in the shaft proximal and distal to the balloon. This report reviews preliminary experimental animal data and initial human clinical experience with this device. In our first study with this device, the duration of inflation in dogs was compared with the maximal duration of inflation using a standard angioplasty catheter. Coronary arteriography was performed to demonstrate distal coronary blood flow through the perfusion balloon catheter. Electrocardiographic recordings and repeated left ventriculograms were performed to detect evidence of ischemia during standard and perfusion and balloon catheter inflations. The average inflation time was 3 +/- 1 minute for the standard catheter and 37 +/- 10 minutes for the perfusion catheter. Each dog had evidence of severe myocardial ischemia during standard inflation, yet none of the animals had ST-segment elevation, ventricular arrhythmia or wall motion abnormality during dilatation with the perfusion catheter. In a second experiment, the effect of prolonged balloon inflations (30 minutes) on intimal hyperplasia was evaluated in the rabbit model. Results of this study showed reduction of intimal and medial hyperplasia after 4 weeks in iliac arteries in rabbits treated with prolonged inflations compared with the contralateral vessel in rabbits treated with standard angioplasty. Initial clinical results from patients treated with this new catheter are presented. The availability of an effective autoperfusion catheter should allow for testing the hypothesis that prolonged inflations could alter the acute angioplasty success rate and long-term restenosis rate.

Use of mechanical devices for distal hemoperfusion during balloon catheter coronary angioplasty

Previous attempts to protect the dependent myocardium during balloon catheter coronary angioplasty in animals and humans have had generally unsatisfactory results. This paper summarizes the authors' experience in investigating commercially available mechanical pumps for distal coronary hemoperfusion during balloon angioplasty. Both roller and piston pumps can attain adequate distal perfusion without significant side effects in the majority of patients. Our goal was to suppress angina for at least 5 min to prolong balloon inflation in awake patients. Minor T-wave changes without concomitant angina pectoris can be expected when the distal coronary bed is perfused with hypothermic blood. Side branch occlusion by the inflated balloon prevents effective protection of the corresponding part of the dependent myocardium during distal hemoperfusion, which may result in persistent angina and ST-T changes uncorrected by increasing the hemoperfusion rate. Distal coronary diffuse spasm, rare and transient, was the only immediate complication of this procedure. It is suggested that intense local wall stimulation could occur with a higher flow rate (jet effect). Improved balloon catheter pressure/flow characteristics and on-line continuous mechanical pumps should soon make distal coronary hemoperfusion through balloon catheters an accepted clinical technique.

Influence of the methodology of percutaneous transluminal coronary angioplasty on restenosis

Restenosis after percutaneous transluminal coronary angioplasty (PTCA) remains the principal factor preventing broader application of this form of myocardial revascularization. Several methodologic variables contribute to the quality of the angioplasty result and may directly or indirectly influence restenosis rates after the procedure. PTCA operators attempt to minimize thrombotic activity at the angioplasty site by delaying PTCA when thrombus is present, with heparin and antiplatelet agents and with thrombolytic agents if thrombus is identified during the procedure. Therapy directed at preventing coronary artery spasm with nitrates and calcium antagonists has no proven efficacy in preventing restenosis. Residual stenosis and pressure gradient have been shown to be predictors of restenosis. Retrospective studies have indicated that a balloon to artery diameter ratio greater than 1 favors long-term patency; however, preliminary results of a prospective randomized study suggested that acute complications were more frequent with larger balloons. The interplay of other balloon-related variables (maximal inflation pressure, number of inflations, duration of inflations, balloon material and length of balloon) and the potential influence on restenosis are discussed. Recommendations for patient management after PTCA are also offered. A number of prospective randomized trials using antiplatelet agents and modification of risk factors are underway to test ability of these strategies to influence restenosis.

Preservation of distal coronary perfusion during prolonged balloon inflation with an autoperfusion angioplasty catheter

A newly designed balloon coronary angioplasty catheter that allows passive antegrade blood flow during balloon inflation (autoperfusion catheter) was compared with a standard balloon coronary angioplasty catheter. In a randomized sequence, inflations were performed for 3 min in the left circumflex coronary artery of 12 dogs with the standard catheter followed by the autoperfusion catheter or vice versa. During inflation with the standard catheter, the ST segment of standard limb lead II increased from -0.02 +/- 0.03 mV to 0.39 +/- 0.08 mV (p less than .001), whereas during inflation with the autoperfusion catheter the ST segment did not change (-0.03 +/- 0.03 vs -0.01 +/- 0.04 mV; p = NS). Regional myocardial blood flow measured by the radioactive microsphere technique in the posterior subepicardium and subendocardium was 0.12 +/- 0.03 and 0.08 +/- 0.03 ml/min/g, respectively, with the standard catheter as compared with 0.57 +/- 0.08 and 0.61 +/- 0.14 ml/min/g with the autoperfusion catheter (both p less than .01 compared with the standard catheter). Thus, unlike the standard catheter, the autoperfusion catheter allows for inflations up to 3 min in duration without producing deleterious changes in the ST segment or severe reductions in regional myocardial blood flow.