Long-term stability of a coronary stent coating post-implantation.

A coronary stent possessing a phosphorylcholine-based polymer coating was removed from a human patient 6 months after implantation and analyzed for the presence of the coating. An atomic force microscopy (AFM) technique has been employed to scrape away several 10- micro m(2) areas on the struts of the explanted stent. Scanning-electron microscopy (SEM) and tapping-mode AFM confirmed a surface coating had been removed in each case. Cross-sectional analysis and force-of-removal measurements showed that both coating depth and hardness were characteristic of that for the phosphorylcholine- (PC-) based coating prior to implantation. AFM amplitude-phase and distance curves from the explanted stent were comparable to those obtained when an unused stent was analyzed. Furthermore, laser ablation high-resolution inductively coupled-plasma mass spectometery (LA-HR-ICP-MS) was used to detect the low level of silicon present in the PC coating after explantation. The results from these techniques confirm that the stent coating is the original PC polymer and is not of biological origin, and support the long-term stability of the coating in vivo.

Improved clinical outcome after widespread use of coronary-artery stenting in Canada.

BACKGROUND: The introduction and refinement of coronary-artery stenting dramatically changed the practice of percutaneous coronary revascularization in the mid-1990s. We analyzed one-year follow-up data for all percutaneous coronary interventions performed in a large, unselected population in Canada to determine whether the use of coronary stenting has been associated with improved outcomes. METHODS: Prospectively collected data on all percutaneous coronary interventions performed on residents of British Columbia, Canada, between April 1994 and June 1997 were linked to province-wide health care data bases to provide the date of the following end points: subsequent target-vessel revascularization, myocardial infarction, and death. Baseline characteristics and procedural variables were identified and Kaplan-Meier survival curves were generated for 9594 procedures divided into seven groups, one for each sequential half-year period. RESULTS: The overall burden of coexisting illnesses remained stable throughout the study period. A large increase in the rate of coronary stenting (from 14.2 percent in the period from April to June 1994 to 58.7 percent in the period from January to June 1997) was associated with a significant reduction in the rate of adverse cardiac events at one year (from 28.8 percent to 22.8.percent; adjusted relative risk, 0.79; 95 percent confidence interval, 0.69 to 0.90; P<0.001). This reduction in adverse events was exclusively due to a large reduction in subsequent target-vessel revascularization (from 24.4 percent to 17.0 percent; adjusted relative risk, 0.72; 95 percent confidence interval, 0.62 to 0.83; P<0.001) without significant changes in the overall rates of myocardial infarction (5.4 percent, P=0.28) or death (3.9 percent, P=0.65). CONCLUSIONS: The need for target-vessel revascularization during one year of follow-up decreased after percutaneous coronary intervention during the mid-1990s. The reduction was coincident with the introduction and subsequent widespread use of coronary stenting.

Early and intermediate term clinical outcome after multiple coronary stenting.

OBJECTIVE: To examine the immediate and intermediate term clinical outcome of multiple coronary stenting. DESIGN: Consecutive patients were prospectively entered on a dedicated database. Follow up information was obtained from outpatient and telephone interviews with patients and family physicians. SETTING: A tertiary referral centre. PATIENTS: 140 consecutive patients underwent multiple coronary stenting between April 1994 and November 1996. Most patients had unstable coronary syndromes. MAIN OUTCOME MEASURES: Death, cerebrovascular accidents, myocardial infarction (MI), coronary artery bypass surgery (CABG), and repeat angioplasty (PTCA). RESULTS: The angiographic success rate was 100% and the clinical procedural success rate 93%. The mean (SD) follow up was 11.9 (7.2) months (range 2-32). The mean (SD) number of stents per patient was 2.4 (0.7). The mean (SD) number of lesions treated per patient was 1.4 (0.6). There were four in-hospital deaths (2.9%) and five patients (3.6%) had an MI before hospital discharge. All in-hospital deaths occurred in patients presenting with an acute MI and cardiogenic shock. Three patients (2.2%) had a late MI. One patient with stent thrombosis underwent emergency CABG. Three patients (2.2%) underwent late CABG. Eight patients (5.7%) had a repeat PTCA. Eighty three patients (61.5%) were asymptomatic at follow up and 121 (86.4%) were free from major clinical events. CONCLUSION: In an era of increased operator experience, high pressure stent deployment, and reduced anticoagulation with antiplatelet treatment alone, multiple coronary stenting may be performed with a high procedural success rate and good intermediate term outcome.

Multiple coronary stenting in unstable angina: early and late clinical outcomes.

We examined clinical outcomes in 110 consecutive patients with unstable angina who underwent multiple coronary stenting over a 32-mo period. The main outcome measures were death, stroke, myocardial infarction, bypass surgery, and repeat angioplasty. The angiographic success rate was 100%, and the procedural success rate was 96%. There were no in-hospital deaths and five (4.5%) patients had a myocardial infarction prior to discharge. There were four (3.6%) stent thromboses with one (0.9%) patient requiring urgent bypass surgery and two (1.8%) requiring repeat angioplasty. At late follow-up (11.9+/-7.1 mo), there was (0.9%) death and three patients (2.8%) suffered myocardial infarction. Three (2.8%) patients underwent late bypass surgery and five (4.6%) had a repeat angioplasty. At follow-up, 86% of patients were event free. We conclude that multiple coronary stenting in unstable angina may be performed with a high procedural success rate and good long-term outcome.

Clinical outcomes of patients more than one year following randomization in the Canadian Coronary Atherectomy Trial (CCAT).

BACKGROUND: The Canadian Coronary Atherectomy Trial (CCAT) assessed, in a randomized comparison, the clinical and angiographic outcomes following atherectomy with those following balloon angioplasty for the treatment of de novo lesions in the proximal one-third of the left anterior descending artery (LAD). Although the procedural success rate was somewhat higher and the postprocedure lumen larger in patients treated with atherectomy, lumen dimensions, restenosis rates and clinical outcomes were similar in the two groups at six months. To determine whether late differences emerged between the groups, clinical follow-up was obtained at a median of 18 (range 10 to 31) months after randomization. METHODS AND RESULTS: Patients were contacted monthly by telephone for the first six months. Subsequent follow-up information was obtained in 272 (99%) of the 274 randomized patients via a clinic visit or telephone interview with the patient and/or a relative. Additional information was obtained from the referring physician as required. There were no differences in adverse events between the two groups during follow-up. In patients randomized to atherectomy compared with balloon angioplasty, death occurred in 1.5% versus 2.2% (cardiac death 0.7% versus 0.7%); myocardial infarction in 5.1% versus 5.9% (Q wave 1.5% versus 1.5%); coronary bypass surgery in 13.1% versus 12.6%; and repeat target lesion intervention in 22.6% versus 21.5%. Persistent or recurrent Canadian Cardiovascular Society class III/IV angina not treated by a further intervention was present in 1.5% versus 2.2%. The combined end-point of death or nonfatal myocardial infarction occurred in nine (6.6%) versus 11 (8.1%) patients and any adverse cardiac event in 50 (36.5%) versus 53 (39.3%). Multivariate logistic regression indicated that unstable angina, reference vessel size and preprocedure minimum lumen diameter were the only variables independently associated with adverse events. CONCLUSIONS: The initial choice of directional atherectomy or balloon angioplasty had no impact on clinical outcome over a period of 18 months in this patient population. With either technique, just over 60% of patients with proximal LAD disease experienced sustained symptomatic improvement without an adverse event following a single procedure, and 80% achieved this status following a repeat percutaneous intervention.

Left main intervention revisited: early and late outcome of PTCA and stenting.

We reviewed our experience with 28 unselected, consecutive patients undergoing left main coronary artery (LMCA) angioplasty who had been considered unsuitable for coronary artery bypass graft surgery (CABG). Fourteen patients (50%) had a protected LMCA circulation. Balloon angioplasty was performed in 11 patients (39.3%), and stents were implanted in 17 patients (60.7%). The procedure was elective in 22 patients (78.6%) and acute in the setting of myocardial infarction/cardiogenic shock in 6 (21.4%). The mean follow-up duration was 15.9 +/- 12 months. There were 5 early (before hospital discharge) and 4 late deaths (total 32.1%), 1 myocardial infarction (3.6%), 6 repeat angioplasties (21.4%), and 3 subsequent CABG (10.7%). All 5 early deaths occurred in patients with cardiogenic shock and unprotected circulation. The results of our study suggest that when patients have prohibitive surgical risks, elective LMCA angioplasty and/or stenting may be undertaken with a high procedural success rate. However, our data do not support intervention in the presence of acute myocardial infarction/cardiogenic shock.

Comparison of bailout versus elective stenting: time to reassess our benchmarks of outcome.

The aim of this study was to compare the clinical outcome of elective and bailout stenting in an era of improved stent deployment techniques and antithrombotic therapy. We retrospectively analysed 136 consecutive patients undergoing stent implantation over a 15 mo period. There was no significant difference in the follow-up duration, length of hospital stay, or the total incidence of major complications between the two groups. Bailout stenting, as compared to elective stenting, was not associated with an increased incidence of in-hospital (no death vs. 1.4%, 4.6% non-Q myocardial infarction vs. 0%, 7.7% vascular complications vs. 7.0%) or late complications (no death vs. 1.4%, no non-Q myocardial infarction vs. 2.8%, 3.1% repeat angioplasty vs. 5.6%, 1.5% coronary artery bypass surgery vs. 1.4%). Stents can be implanted in cases of failed angioplasty with a success rate similar to that of elective stent implantation with a low incidence of complications and equivalent clinical outcome.

Antiplatelet therapy alone is safe and effective after coronary stenting: observations of a transition in practice.

OBJECTIVE: To evaluate the safety and efficacy of transition in practice after coronary stenting to antiplatelet therapy alone compared with anticoagulation with warfarin. DESIGN: Retrospective analysis of coronary stent management in a tertiary Canadian centre. PATIENTS: A total of 136 consecutive patients (146 lesions) were analyzed who underwent Palmaz-Schatz coronary stenting over a 15-month period and were treated with anticoagulation with warfarin (56 patients) or antiplatelet therapy alone with ticlopidine and acetylsalicylic acid (80 patients) during the transition in poststenting therapy in the authors' practice. Treatment was continued for 30 days in both groups. High pressure stent deployment was used in the majority of cases (greater than 90%), and use of intravascular ultrasound was infrequent (less than 12%). MAIN RESULTS: At 30 days, there were no clinical manifestations of stent thrombosis, coronary artery bypass surgery or repeat angioplasty in either group. One death occurred in the antiplatelet group. Periprocedural non-Q wave myocardial infarction occurred in two patients in the antiplatelet group and in one patient in the warfarin group. There was a significantly higher incidence of vascular complications in the warfarin group than in the antiplatelet group (14.3% versus 2.5%, respectively, P = 0.04). The length of hospital stay was significantly shorter in the antiplatelet group than in the warfarin group (3.0 +/- 1.8 versus 6.7 +/- 2.6 days, respectively, P < 0.001). CONCLUSIONS: Reduced anticoagulation with antiplatelet therapy alone after coronary stenting, despite infrequent use of intravascular ultrasound, is an effective and safe strategy with a low rate of vascular complications, a relatively short hospital stay and a low incidence of clinical manifestations of stent thrombosis.

On line ST-segment analysis for detection of myocardial ischaemia during and after coronary revascularization.

PURPOSE: A paucity of information exists to validate the accuracy and reliability of ECG monitoring in the operating room or ICU. The purpose of this study was to determine the accuracy, sensitivity, specificity, and predictive values of the Marquette ECG monitor for detection of perioperative myocardial ischaemia (PMI) as measured by ST segment changes in a high risk population. METHODS: Monitoring for PMI in 28 patients scheduled for aortocoronary bypass surgery was done with the Cardiodata PR ambulatory continuous electrocardiography (ACECG) monitor lead V5, and compared with lead V5 of the Marquette Series 7000 ECG/Surgical operating room monitor, and ECG/Resp ICU monitor. The Marquette lead V5 was evaluated using current criteria for the assessment of diagnostic tests including concordance, sensitivity, specificity, positive and negative predictive values, false positive and false negative rates and compared with the ACECG monitor which served as the reference or "gold standard." Agreement beyond chance between the two methods was assessed using the Kappa statistic. RESULTS: Of the 53 observation data points, 27 were defined as ischaemic episodes by ACECG. Concordance between lead V5 in each system was 83% (44/53 episodes). Discordance was 17% (9/53 episodes), predominantly in the postbypass interval (77%, 7/9; P = 0.0184). The incidences of false negatives and false positives for Marquette lead V5 was 26% (7/27) and 7.7% (2/26), respectively. The sensitivity and specificity of the Marquette was 0.74 and 0.92. Positive predictive value was 0.91, negative predictive value was 0.77, and Kappa statistic was 66%. CONCLUSION: Automated ST segment analysis with the Marquette Series 7000 monitoring system demonstrates good diagnostic accuracy, moderate sensitivity, and high specificity. However, clinically significant false negative and false positive rates of ischaemia detection are associated with its use, especially in the postoperative period.

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.

Pulmonary hypertension associated with primary biliary cirrhosis in the absence of portal hypertension: a case report.

Pulmonary hypertension is well described in association with portal hypertension of any cause including end stage primary biliary cirrhosis (PBC). The essential feature of this association is the presence of portosystemic shunting, including surgically created shunts. A patient with primary pulmonary hypertension and PBC without portal hypertension is reported. This suggests that primary pulmonary hypertension may be associated with PBC in the absence of portal hypertension. Decisions regarding appropriate organ transplantation may depend on whether pulmonary hypertension is primary or secondary to portal hypertension.

A comparison of directional atherectomy with balloon angioplasty for lesions of the left anterior descending coronary artery.

BACKGROUND: Restenosis is a major limitation of coronary angioplasty. Directional coronary atherectomy was developed with the expectation that it would provide better results than angioplasty, including a lower rate of restenosis. We undertook a randomized, multicenter trial to compare the rates of restenosis for atherectomy and angioplasty when used to treat lesions of the proximal left anterior descending coronary artery. METHODS: Of 274 patients referred for first-time, non-surgical revascularization of lesions of the proximal left anterior descending coronary artery, 138 were randomly assigned to undergo atherectomy and 136 to undergo angioplasty; 257 of 265 eligible patients (97 percent) underwent follow-up angiography at a median of 5.9 months. Computer-assisted quantitative measurements of luminal dimensions were determined from the angiograms obtained before and immediately after the procedure and at follow-up. The primary end point of restenosis was defined as stenosis of more than 50 percent of the vessel's diameter at follow-up. RESULTS: Quantitative analysis showed that the procedural success rate was higher in patients who underwent atherectomy than in those who had angioplasty (94 percent vs. 88 percent, P = 0.061); there was no significant difference in the frequency of major in-hospital complications (5 percent vs. 6 percent). At follow-up, the rate of restenosis was 46 percent after atherectomy and 43 percent after angioplasty (P = 0.71). Despite a larger initial gain in the minimal luminal diameter with atherectomy (mean [+/- SD], 1.45 +/- 0.47 vs. 1.16 +/- 0.44 mm; P < 0.001), there was a larger late loss (0.79 +/- 0.61 vs. 0.47 +/- 0.64 mm; P < 0.001), resulting in a similar minimal luminal diameter in the two groups at follow-up (1.55 +/- 0.60 vs. 1.61 +/- 0.68, P = 0.44). The clinical outcomes at six months were not significantly different between the two groups. CONCLUSIONS: The role of atherectomy in percutaneous coronary revascularization remains to be fully defined. However, as compared with angioplasty, atherectomy did not result in better late angiographic or clinical outcomes in patients with lesions of the proximal left anterior descending coronary artery.

Double Marker ACX II: a new balloon catheter for coronary stent delivery.

We report our initial experience using the Double Marker ACX II for intracoronary stent deployment in 22 patients, 10 of whom were elective stents and 12 of whom were stented for complications following failed coronary angioplasty. The overall success rate was 95 percent. This dilatation catheter offers advantages which include accurate stent deployment with a double marker system, the option of using a delivery sheath, and the ability to deliver multiple stents with the same balloon catheter.

Preliminary experience at a Canadian centre with directional coronary atherectomy for complex lesions.

OBJECTIVE: To evaluate preliminary experience of directional coronary atherectomy for complex coronary artery lesions. DESIGN: Nonrandomized, sequential patients with coronary arterial lesions that were ostial, eccentric, bulky, recurrent or membranous. SETTING: Cardiac catheterization laboratory of a tertiary referral general hospital. PATIENTS: Twenty-three patients with angina pectoris refractory to medical therapy who were suitable candidates for coronary bypass surgery. INTERVENTIONS: Directional coronary atherectomy with associated balloon angioplasty, if required, to reduce lesion stenosis to less than 25%. MAIN RESULTS: Primary success was achieved in 29 of 33 lesions (88%) by atherectomy alone and in 31 of 33 lesions (94%) by additional use of balloon angioplasty. Atherectomy retrieved tissue in 30 of 33 attempts (91%). One patient suffered Q wave myocardial infarction; one had acute occlusion after atherectomy requiring emergency balloon angioplasty; and one required repair of a false aneurysm of the femoral artery. CONCLUSIONS: Directional coronary atherectomy is safe and efficacious for ostial, bulky and eccentric lesions not optimally suited to balloon angioplasty. Lesions which have tortuous segments immediately beyond, restricting movement of the stiff nose-cone, and which are membranous or bandlike, may not be indicated for directional coronary atherectomy.

Balloon embolization of latrogenic aortocoronary arteriovenous fistula.

A detachable latex balloon was used to occlude an iatrogenic aortocoronary arterio-venous fistula. The aim of providing retrograde myocardial perfusion was not achieved to any significant degree because of rapid recruitment of collateral venous routes to the coronary sinus. This may have implications for the effectiveness of deliberate grafting of the coronary venous system with proximal venous ligation, as has been recommended when the coronary arterial system is small and diffusely diseased.