P2807Clinical outcomes with cobalt chromium biolimus eluting drug-eluting stents compared with stainless steel biolimus eluting drug-eluting stents in all-comers patients

Aims

Thinner stent struts may improve deliverability, conformability and reduce vessel injury. We report the first clinical outcomes of the thinner strut (84–88um) cobalt chromium biolimus eluting stent from the Biomatrix Alpha registry and compare these with objective performance criteria from the stainless steel BioMatrix Flex arm of the Leaders study.

Methods

A total of 1257 patients were studied: 400 patients from 12 centres receiving ≥1 Biomatrix Alpha stent were prospectively enrolled into the Biomatrix Alpha registry and then underwent a pre-specified comparison with 857 patients who received a Biomatrix Flex stent in the Leaders study. The primary endpoint was major adverse cardiac events (MACE) defined as the composite of cardiac death, myocardial infarction (MI) or clinically driven target vessel revascularization (TVR) at 9 months. Assuming a 9.2% event rate with BioMatrix Flex, a one-sided type I error (α) of 0.05, and a 4% non-inferiority margin, a sample size of 400 in the Biomatrix alpha registry had >80% power to conclude non-inferiority.

Results

Baseline characteristics in the Alpha registry were typical of an all-comers population with a mean age of 64.7±11.3, diabetes 19%, current smoking 21%, dyslipidemia 57%, hypertension 57%, total stent length per lesion 25.49±13.45, mean stents per procedure 1.59±0.88 and overlapping stents in 13.4%. Observed MACE at 9 months with Alpha was 3.94% (upper limit 5.98%) vs. 9.28% MACE rate with Flex stents in Leaders, which met pre-specified criteria for non-inferiority (p<0.001) and on post hoc testing for superiority yielded p<0.001 for Alpha vs Flex. Secondary endpoints with Alpha included clinically-driven TVR 2.6%, all-cause mortality rate 1.51% and definite/probable stent thrombosis 0.25%.

While both Alpha and Leaders enrolled all-comers, Alpha included longer total stent length per lesion (25.49 vs 23.85mm, p<0.001) and more stents per procedure (mean 1.59 vs 1.34; p<0.001) but fewer patients with diabetes (19% vs 26%; p=0.0087), dyslipidemia (57 vs 65%; p=0.0037), prior MI (18.8% vs 32.2%; p<0.001) or acute coronary syndrome (41% vs 55%; p<0.001). To correct for these imbalances and to assess robustness further, a propensity score at the patient level data was undertaken (total sample size of 1257 patients; 400 from the Alpha registry and 857 from the LEADERS study). A propensity score stratification method was used obtaining 5 quintiles for adjusted analysis (each of the 5, containing 251 or 252 patients, 20%). In each of the strata as well as at the aggregate level, a p valve<0.005 was obtained confirming non-inferiority for the primary endpoint.

Conclusion

The thinner strut (84–88um) cobalt chromium Biomatrix Alpha stent demonstrated low MACE rates at 9 months which were non-inferior to MACE outcomes with the stainless steel Biomatrix Flex in the Leaders study. The robustness of this finding was further confirmed by a propensity score analysis.

Acknowledgement/Funding

Biosensors

P2797Clinical outcomes of an ultra-thin strut sirolimus-eluting stent with biodegradable polymer in all-comers patients undergoing coronary intervention

Background

Thin stent struts may be associated with reduced vessel injury and use of biodegradable polymers may further improve long term outcomes. However, data with earlier stents has been inconsistent; thus further studies with newer devices are needed.

Purpose

To evaluate the efficacy and safety of a new ultra-thin (65um) strut cobalt chromium sirolimus-eluting stent with a hybrid design (closed cell at ends and open cells in middle to reduce edge injury and optimise conformability) in all-comers patients undergoing percutaneous coronary intervention (PCI).

Methods

We enrolled 752 patients from 14 sites undergoing PCI into a prospective, non-randomised, multi-centre, open-label, observational registry. Inclusion of patients with complex anatomy (long stent lengths, bifurcations and chronic total occlusions) was encouraged. Clinical follow-up was scheduled at 1, 9, 12 and 24 months. The primary endpoint was incidence of major adverse cardiac events (MACE) - cardiac death, non-fatal myocardial infarction (MI), or target vessel revascularization (TVR) - at 9 months.

Results

Mean patient age was 64.7±12.2 years, 20.7% had diabetes, 58.8% had dyslipidaemia, 40.4% had multi-vessel disease, 22% had previous PCI, 4.7% had previous coronary-artery bypass graft, and 19.6% had a clinical history of previous MI. Mean lesion length was 25.7±17.3 mm. The primary endpoint of cumulative MACE up to 9 months (from 624 patients reaching 9 months follow-up) occurred in 12 patients (1.92%), including 6 (0.96%) cardiac death, 5 (0.80%) MI and 6 (0.96%) clinically indicated TVR. Definite stent thrombosis was reported in 3 patients (0.48%) and probable stent thrombosis in 2 patients (0.32%).

Conclusions

Use of an ultra-thin strut biodegradable polymer sirolimus-eluting stent in all-comers patients undergoing PCI was associated with good clinical efficacy and safety.

Acknowledgement/Funding

Meril Life

Is there a Failure to Optimize theRapy in anGina pEcToris (FORGET) study?

BACKGROUND

In the management of chronic stable angina, percutaneous coronary intervention (PCI) provides symptomatic relief of angina rather than improvement of prognosis. Current guidelines recommend optimization of medical therapy prior to elective PCI. It is not clear if these guidelines are adhered to in clinical practice.

AIM

The aim of this multi-centre study was to determine the extent to which these treatment guidelines are being implemented in the UK.

DESIGN

This was a multi-centre study involving six hospitals in the UK.

METHODS

The medical treatment and extent of risk factor modification was recorded for consecutive patients undergoing elective PCI for chronic stable angina at each site. Data collected included anti-anginal drug therapy, lipid levels and blood pressure (BP). Data on heart rate (HR) control were also collected, since this represents a fundamental part of medical anti-anginal therapy. Target HR is <60 b.p.m. for symptomatic angina.

RESULTS

A total of 500 patients [74% male; mean age +/- SD (64.4 +/- 10.1 years)] were included. When considering secondary prevention, 85% were receiving a statin and 76% were on an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker. In terms of medical anti-ischaemic therapy, 78% were receiving beta-blockers [mean equivalent dose of bisoprolol 3.1 mg (range 1.25-20 mg)], 11% a rate limiting calcium antagonist, 35% a nitrate or nicorandil and one patient was receiving ivabradine. The mean total cholesterol (95% confidence interval) was 4.3 mmol/l (4.2-4.4), mean systolic BP of 130 +/- 24 mmHg and mean diastolic BP of 69 +/- 13 mmHg. Serum cholesterol was <5 mmol/l in 77% and <4 mmol/l in 42% of the patients, 62% of the patients had systolic BP < 140 mmHg and 92% had diastolic BP < 90 mmHg. Considering European Society of Cardiology targets, 50% had systolic BP < 130 mmHg and 76% had diastolic BP < 80 mmHg. A large proportion of patients did not achieve target resting HR; 27% of patients had a resting HR of >or=70 b.p.m., 40% had a resting HR between 60 and 69 b.p.m. and 26% had a resting HR between 50 and 59 b.p.m. The resting HR was not related to the dose of beta-blocker.

CONCLUSION

A significant proportion of the patients with chronic stable angina undergoing elective PCI did not achieve therapeutic targets for lipid, BP and HR control. Over 50% of patients did not receive adequate HR lowering anti-anginal therapy to achieve recommended target resting HR.

Body surface mapping improves early diagnosis of acute myocardial infarction in patients with chest pain and left bundle branch block

OBJECTIVE

To test prospectively depolarisation and repolarisation body surface maps (BSMs) for mirror image reversal, which is less susceptible to artefact, in patients with acute ischaemic-type chest pain, and to compare these BSM criteria with previously published 12 lead ECG criteria.

METHODS

An 80 lead portable BSM system was used to map patients presenting with acute ischaemic-type chest pain and a 12 lead ECG with left bundle branch block (LBBB). Acute myocardial infarction (AMI) was defined by serial cardiac enzymes. Each 12 lead ECG was assessed by the criteria of Sgarbossa et al and Hands et al for diagnosis of AMI. Depolarisation and repolarisation BSMs were assessed for loss of mirror image reversal of QRS with ST-T isointegral map patterns and a change in vector angle from QRS to ST-T outside 180+/-15 degrees -findings typically seen in LBBB with AMI.

RESULTS

Of 56 patients with chest pain and LBBB, 18 had enzymatically confirmed AMI. Patients with loss of BSM image reversal were significantly more likely to have AMI (odds ratio 4.9, 95% confidence interval 1.5 to 16.4, p = 0.007). Loss of BSM image reversal was significantly more sensitive (67%) for AMI than either 12 lead ECG method (17%, 33%) albeit with some loss in specificity (BSM 71%, 12 lead ECG 87%, 97%). Patients with AMI compared with those without AMI had a greater mean change in vector angle outside the normal range (180+/-15 degrees ), particularly between QRS isointegral and ST60 isopotential (the potential 60 ms after the J point at each electrode site) BSMs (19 degrees v 9 degrees, p = 0.038). Loss of image reversal and QRS-ST60 vector change outside 180+/-15 degrees had 61% sensitivity and 82% specificity for AMI (odds ratio 7.0, 95% confidence interval 2.0 to 24.4, p = 0.001).

CONCLUSIONS

BSM compared with the 12 lead ECG improved the early diagnosis of AMI in the presence of LBBB.

Impact of pre-hospital care in patients with acute myocardial infarction compared with those first managed in-hospital

AIMS

To compare prospectively the impact of pre-hospital care by a physician-staffed mobile coronary care unit with patients managed initially in-hospital, all with acute myocardial infarction.

METHODS AND RESULTS

This was a single centre registry of consecutive patients (n=750) admitted with acute myocardial infarction to the coronary care unit and cardiology wards of the Royal Victoria Hospital, Belfast between 1998 and 2001. For the 750 patients, in-hospital mortality was 11% and was significantly lower for those managed pre-hospital (8% vs 13%, P=0.04): patients who received fibrinolytic therapy (n=474), the in-hospital mortality was significantly lower in the pre-hospital group (7% vs 13%, P=0.02). Those managed pre-hospital had significant reduction in the median delay times (25th, 75th percentiles) from onset of symptoms to call for help 1.0 (0.5, 2.2) vs 2.0 (0.9, 6.0) h, P<0.001, from call for help to receiving fibrinolytic therapy 1.0 (0.8, 1.5) vs 1.8 (1.2, 2.5) h, P<0.001 resulting in a shorter pain-to-needle time for fibrinolytic therapy 2.3 (1.5, 3.8) vs 4.0 (2.6, 7.2) h, P<0.001. For all patients, older age, haemodynamic indicators on admission (hypotension, higher heart rate, heart failure) and managed by the in-hospital route were significant independent variables for an adverse in-hospital mortality. Although for patients aged >or=75 years no statistical significant reduction in mortality occurred for those managed pre-hospital (P=0.051), nevertheless patients in this age group first treated pre-hospital who received fibrinolytic therapy had a significantly lower mortality than those first treated in-hospital (21% vs 43%, P=0.02).

CONCLUSIONS

Consecutive patients with acute myocardial infarction seen and managed initially out-of-hospital by a physician-staffed mobile coronary care unit had significantly lower in-hospital mortality.

Randomized comparison of enoxaparin with unfractionated heparin following fibrinolytic therapy for acute myocardial infarction

AIMS

To compare the efficacy and safety of low molecular weight heparin with unfractionated heparin following fibrinolytic therapy for acute myocardial infarction.

METHODS AND RESULTS

Three-hundred patients receiving fibrinolytic therapy following acute myocardial infarction were randomly assigned to low molecular weight heparin as enoxaparin (40 mg intravenous bolus, then 40 mg subcutaneously every 8 h, n=149) or unfractionated heparin (5000 U intravenous bolus, then 30 000 U. 24 h(-1), adjusted to an activated partial thromboplastin time 2-2.5x normal, n=151) for 4 days in conjunction with routine therapy. Clinical and therapeutic variables were analysed, in addition to use of enoxaparin or unfractionated heparin, to determine independent predictors of the 90-day composite triple end-point (death, non-fatal reinfarction, or readmission with unstable angina). The triple end-point occurred more frequently in patients receiving unfractionated heparin rather than enoxaparin (36% vs. 26%; P=0.04). Logistic regression modelling of baseline and clinical variables identified the only independent risk factors for recurrent events as left ventricular failure, hypertension, and use of unfractionated heparin rather than enoxaparin. There was no difference in major haemorrhage between those receiving enoxaparin (3%) and unfractionated heparin (4%).

CONCLUSION

Use of enoxaparin compared with unfractionated heparin in patients receiving fibrinolytic therapy for acute myocardial infarction was associated with fewer recurrent cardiac events at 90 days. This benefit was independent of other important clinical and therapeutic factors.