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

Candidate gene susceptibility variants predict intermediate end points but not angiographic coronary artery disease

BACKGROUND

Moderate-sized studies have suggested that variants of candidate genes can influence laboratory markers of coronary artery disease (CAD), but whether they predict parallel changes in clinical CAD risk is unknown.

METHODS

We studied a single nucleotide polymorphism (SNP) from each of the 5 candidate genes for intermediate (laboratory) and clinical (angiographic CAD) end points in a large cohort of patients. The 5 gene SNPs were cholesteryl ester transfer protein (CETP) TaqIB (N = 3219), ATP-binding cassette (ABCA1) G596A (N = 3302), lipoprotein lipase (LPL) HindIII (N = 909), plasminogen activator inhibitor, type 1 (PAI1), 4G/5G (N = 1142), and hepatic lipase (HL) C-541T (N = 4704). Intermediate outcomes were high-density lipoprotein cholesterol (HDL-C) and triglycerides (TGs). Cases had 1- to 3-vessel CAD (> or = 70% stenosis); controls had angiographically normal coronaries.

RESULTS

Cholesteryl ester transfer protein predicted HDL (mean, B1B1 35.0 mg/dL, B2B2 38.6 mg/dL; P < .001) but not CAD (B1B1 74%, B2B2 70%; adjusted P = .35, odds ratio [OR] = 0.89). ABCA1 predicted HDL (mean, GG = 36.4 mg/dL, AA = 39.2 mg/dL; P = .02) but not CAD (GG 74%, AA 75%; adjusted P = .96, OR = 0.99). HL predicted HDL (CC 37.1 mg/dL, TT 40.9 mg/dL; P = .002) but not CAD (CC 71%, TT 68%, adjusted P = .66, OR = 0.94). LPL predicted TG (median: [++] 134, [--] 98 mg/dL; P < .001) but not CAD ([++] 79%, [--] 79%; adjusted P = .99, OR = 1.00). PAI1 predicted TG (median, 4G4G 130 mg/dL, 5G5G 148 mg/dL; P = .16), but not CAD (4G4G 77%, 5G5G 76%; adjusted P = .62, OR = 1.11).

CONCLUSIONS

Five SNPs predicted differences in risk-related lipids but not angiographic CAD. These discrepancies suggest that genetic determinants of CAD are complex and intermediate phenotypes are poor surrogates. These findings have important implications for future directions in genetic research.

Prognostic significance of myocardial enzyme release after coronary interventions

Mild to moderate periprocedural elevation in CK with concurrent CK MB elevation result in increased subsequent myocardial infarction and mortality. However the potential risks that percutaneous revascularization interventions pose must be evaluated in light the risks of alternative procedures and the risks of continued medical management. Prospective clinical trials examining the relationship of periprocedural enzyme elevations to long term prognosis will need to address this issue.

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.

Device implementation, validation, and application assessment of two continuous 12-lead ECG monitors during percutaneous transluminal coronary angioplasty: description of the validation method and implications for clinical trials

Comparability of clinical and research data sets may be undermined if the instruments used to acquire them vary. Even when standard 12-lead electrocardiographic formats are used for monitoring, proprietary signal processing techniques and sampling intervals may differ among devices. In order to directly compare the two commercially available standard 12-lead devices with monitoring capabilities, bifurcated wires from a single standard lead set were attached to each device in elective angioplasty patients. Neither device was used as a standard; rather, a method was designed to analyze the output from each device independently, and then, if results differed, data from both monitors were reviewed by consensus to determine the source of the differences. Analysis endpoints for each study included study quality, baseline ST-segment levels, the presence of ischemia, number of ischemic episodes, peak lead location, and peak lead amplitude. Sources of differences in these endpoints visible to consensus review included variations between devices in baseline stability, noise/artifact levels, stability of the QRS complex onset, and temporal sampling intervals.

Myonecrosis after revascularization procedures

The detection of elevated cardiac enzyme levels and the occurrence of electrocardiographic (ECG) abnormalities after revascularization procedures have been the subject of recent controversy. This report represents an effort to achieve a consensus among a group of researchers with data on this subject. Creatine kinase (CK) or CK-MB isoenzyme (CK-MB) elevations occur in 5% to 30% of patients after a percutaneous intervention and commonly during coronary artery bypass graft surgery (CABG). Although Q wave formation is rare, other ECG changes are common. The rate of detection is highly dependent on the intensity of enzyme and ECG measurement. Because most events occur without the development of a Q wave, the ECG will not definitively diagnose them; even the ECG criteria for Q wave formation signifying an important clinical event have been variable. At least 10 studies evaluating > 10,000 patients undergoing percutaneous intervention have demonstrated that elevation of CK or CK-MB is associated not only with a higher mortality, but also with a higher risk of subsequent cardiac events and higher cost. Efforts to identify a specific cutoff value below which the prognosis is not impaired have not been successful. Rather, the risk of adverse outcomes increases with any elevation of CK or CK-MB and increases further in proportion to the level of intervention. This information complements similar previous data on CABG. Obtaining preprocedural and postprocedural ECGs and measurement of serial cardiac enzymes after revascularization are recommended. Patients with enzyme levels elevated more than threefold above the upper limit of normal or with ECG changes diagnostic for Q wave myocardial infarction (MI) should be treated as patients with an MI. Patients with more modest elevations should be observed carefully. Clinical trials should ensure systematic evaluation for myocardial necrosis, with attention paid to multivariable analysis of risk factors for poor long-term outcome, to determine the extent to which enzyme elevation is an independent risk factor after considering clinical history, coronary anatomy, left ventricular function and clinical evidence of ischemia. In addition, tracking of enzyme levels in clinical trials is needed to determine whether interventions that reduce periprocedural enzyme elevation also improve mortality.

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.

Oscillating balloon angioplasty: does pressure oscillation reach the balloon?

Oscillating pressure inflations may minimize trauma to the coronary artery during coronary angioplasty. We measured in vitro diameters of polyolepin copolymer compliant angioplasty balloons (as a surrogate for pressure) during pressure oscillation at the inflator to determine if pressure oscillations at the inflator were conducted to the balloon. Balloon diameter oscillation increased as cycle length and inflator pressure amplitude increased. Currently practiced oscillating inflation (cycle length 2-3 sec, amplitude 2-3 atm) did not effectively transmit oscillation to the balloon. Clinically feasible optimal balloon oscillation was achieved at a cycle length of 6 sec and pressure amplitude of about 3 atm.

Intracoronary heparin delivery in humans. Acute feasibility and long-term results

BACKGROUND

Inefficacy of systemic drug administration for restenosis prevention may partially relate to insufficient local drug concentration. This study aimed to evaluate the acute feasibility and long-term outcome of using an infusion-perfusion coil balloon, Dispatch.

METHODS AND RESULTS

In 22 patients after balloon angioplasty, the coil balloon was studied for (1) feasibility of local heparin delivery, (2) symptoms and signs of ischemia during prolonged deployment compared with angioplasty balloon occlusion, (3) coronary pressure and flow distal to the inflated device, and (4) long-term clinical and angiographic results. During prolonged intracoronary deployment of the coil balloon (29 +/- 8 minutes), 5 of 22 patients developed mild chest pain versus 20 of 22 during angioplasty (275 +/- 283 seconds). Neither hemodynamic nor vectorcardiographic signs of ischemia were detected, in contrast to angioplasty balloon occlusion. Baseline flow across the coil balloon was 44 +/- 31 mL/min, increasing by a factor of 1.8 +/- 0.7 during pharmacologically induced hyperemia. A mean volume of 14.2 +/- 6.1 mL containing 1416 +/- 608 IU of heparin was infused locally at a pressure of 122 +/- 54 mm Hg. At 7 +/- 1-month follow-up, 1 asymptomatic patient had died, and of the remaining 21, 17 (81%) were asymptomatic. Angiographic follow-up was obtained in 15 of 21 patients (71%), including all 4 symptomatic patients. Mean minimal luminal diameter after the procedure was 2.16 +/- 0.49 mm and at follow-up, 1.89 +/- 0.45 mm, which corresponds to a restenosis rate (diameter stenosis > or = 50%) of 7% (1/15).

CONCLUSIONS

Intracoronary use of the coil balloon after balloon angioplasty proved to be feasible and subjectively as well as objectively well tolerated during prolonged deployment by virtue of its perfusion properties. High volumes of heparin solution can be infused locally at very low pressure. No unfavorable clinical or angiographic long-term effects were observed.

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

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

Local delivery of r-hirudin by a double-balloon perfusion catheter prevents mural thrombosis and minimizes platelet deposition after angioplasty

BACKGROUND

The major morbidity of percutaneous transluminal coronary angioplasty is acute thrombosis and restenosis of the dilated lesion. Platelet-thrombus deposition occurs within minutes after injury, is primarily mediated by thrombin, causes acute occlusion, and contributes to late restenosis. Experimentally, specific thrombin inhibitors have prevented mural thrombosis. However, local therapy may be more effective than systemic treatment. We tested the hypothesis that high local concentrations of an antithrombin drug at the site of arterial injury following balloon angioplasty inhibit platelet thrombus formation equally or better than conventional systemic treatment and at lower systemic anticoagulant levels.

METHODS AND RESULTS

Balloon angioplasty of the carotid arteries of 29 pigs was performed using systemic intravenous treatment with heparin (100 U/kg, groups I and II), suboptimal r-hirudin (0.3 mg/kg, group III), and higher-dose r-hirudin (0.7 mg/kg, group IV), which is the lowest dose that completely inhibited arterial thrombosis in the pig. Immediately after balloon angioplasty of the first carotid, additional local therapy with placebo (group I) or r-hirudin (groups II, III, and IV; 0.3 mg/kg in 1 mL) was administered with distal perfusion through a new percutaneous double-balloon catheter. After 1 hour of local drug delivery, angioplasty of the contralateral carotid was performed. Reflow for 1 hour was permitted to both carotids to compare the short-term effect of local plus systemic treatment with systemic treatment on quantitative 111In-labeled platelet deposition and macroscopic mural thrombus formation on deeply injured carotid segments. Local drug delivery of placebo compared with systemic heparin treatment resulted in no change of platelet deposition (x 10(6)/cm2, mean +/- SEM) in controls (group I, 91.0 +/- 23.5 versus 80.8 +/- 19.4), but local delivery of r-hirudin resulted in a significant reduction in group II (15 +/- 2.5 versus 71.3 +/- 14.5; P < .02) and group III (11.4 +/- 2.5 versus 80.5 +/- 11.4; P < .01) and was borderline in group IV (7.4 +/- 1.8 versus 14.1 +/- 7.4; P = .05), respectively. The incidence of macroscopic mural thrombus formation with local and systemic treatment was 86% and 75% in group I, 16% and 70% in group II, 14% and 71% in group III, and 0% and 16% in group IV, respectively.

CONCLUSIONS

Local therapy with the specific thrombin inhibitor r-hirudin significantly reduces short-term quantitative platelet deposition and macroscopic mural thrombus formation following balloon angioplasty compared with systemic treatment of conventional doses of heparin and hirudin and requires a significantly smaller amount of the recombinant drug.

Coronary artery dissection caused by exit of the guidewire through the distal perfusion sidehole of an auto-perfusion angioplasty balloon catheter

A previously unrecognized cause of coronary artery dissection is reported. A 67-year-old woman underwent angioplasty of the right coronary artery using an autoperfusion balloon catheter. Dissection occurred because the balloon catheter was advanced while the guidewire exited from one of the distal perfusion sideholes.

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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