Coronary artery size and disease in UK South Asian and Caucasian men.

OBJECTIVE: South Asian patients in the UK have a higher mortality rate after coronary artery bypass grafting (CABG) than Caucasian patients. As coronary artery size has been shown to correlate to outcome from bypass grafting, it has been suggested that smaller coronary arteries in South Asians as compared to Caucasians could contribute to a poorer outcome in the Asian population. We aimed to measure coronary artery size and disease in matched South Asian and Caucasian men undergoing first time coronary artery bypass grafting. METHODS: Coronary arteriograms from 53 matched first generation South Asian and Caucasian men were examined. The patients had no history of myocardial infarction, coronary revascularisation, familial dyslipidaemia, diabetes or renal disease. They were individually matched for age, height, weight, body mass index and body surface area. Thereafter, coronary artery diameters and significant (> or =50%) diameter stenoses were measured in a blinded fashion using quantitative coronary angiography (QCA). RESULTS: In South Asian men, diameters of the left main stem (LMS) and the proximal left anterior descending, the circumflex and the right coronary arteries were 4.6+/-0.9 mm, 3.5+/-0.8 mm, 3.4+/-0.8 mm and 3.5+/-0.8 mm, respectively. The corresponding arterial diameters among Caucasian men (4.5+/-0.9 mm, 3.5+/-0.7 mm, 3.5+/-0.8 mm and 3.8+/-0.8 mm) did not differ from those in South Asians. There was no difference in the number of significant coronary artery stenoses between the two groups and no difference in bypass and cross-clamp times or in adverse outcome (one from each group died after coronary artery bypass grafting). CONCLUSION: Proximal coronary artery size and number of significant coronary stenoses did not differ between matched pairs of South Asian and Caucasian men using strict inclusion/exclusion criteria.

Postoperative infection with meticillin-resistant Staphylococcus aureus and socioeconomic background.

Infectious disease can be linked to social deprivation. We investigated whether postoperative infection with meticillin-resistant Staphylococcus aureus (MRSA) is related to socioeconomic background. Patients were stratified by social deprivation according to postcode. In a consecutive series of 1739 UK residents undergoing isolated coronary artery bypass grafting, 23 (1.3%) were infected with MRSA. We noted a graded relation between incidence of infection and social deprivation. Patients from the most deprived areas had a seven-fold higher infection rate (13 of 579 [2.2%]) than those from the least deprived areas (two of 580 [0.3%]; p=0.0040). Patients with MRSA infection had a six-fold higher mortality rate and a longer hospital stay than patients with no such infection. Our findings suggest that patients from deprived areas might be especially susceptible to postoperative infection with MRSA.

Effect of enhanced external counterpulsation on dobutamine-induced left ventricular wall motion abnormalities in severe chronic angina pectoris.

We studied the effect of enhanced external counterpulsation (EECP) in 23 consecutive patients with stable angina pectoris who had a positive dobutamine stress echocardiogram. After EECP, stress-induced wall motion score (WMS) improved by > or =2 grades in 43% of the patients (n = 10); the average improvement was 5.3 +/- 3.8 compared with -0.6 +/- 3.0 in the remaining 13 patients (p = 0.007). The diastolic/systolic augmentation ratio increased by 217% in response to the full course of EECP (p = 0.0002) among patients with improved WMS, and by 71% (p = 0.004) among the other patients; the increase was greater among patients with improved WMS than among patients with no improvement (p = 0.01). After EECP, Canadian Cardiovascular Society angina class improved from 3.1 +/- 0.6 to 2.2 +/- 0.7 (p <0.0001) in the entire group and exercise capacity increased by 73 seconds (p = 0.0002) in patients who were able to exercise (n = 18).

Excess coronary artery bypass graft mortality among women with hypothyroidism.

BACKGROUND: The impact of thyroid disease on patients undergoing coronary artery bypass grafting has been reported in only small series of selected patients. METHODS: We investigated 30-day mortality of patients on thyroxine replacement therapy undergoing isolated coronary artery bypass grafting from 1993 to 2000 and identified variables of importance for outcome. RESULTS: A total of 3,631 patients (606 women) had isolated coronary artery bypass grafting of whom 58 patients (30 women) were treated for hypothyroidism. The mortality rate was higher among women with thyroxine replacement (16.7%, 95% confidence interval [CI] 5.6 to 34.7) than those without thyroxine replacement (5.9%, 95% CI 4.1 to 8.2; p = 0.02) and no difference between men with (3.6%, 95% CI 0.1 to 17.8) and without (2.6%, 95% CI 2.0 to 3.2) thyroxine treatment (p = 0.8). Intake of diuretics (p < 0.001) was directly associated with mortality whereas intake of aspirin (p = 0.01), levothyroxine dose (p = 0.03), and serum thyroxine level (p = 0.01) were inversely associated with mortality among women on thyroxine replacement. CONCLUSIONS: Women on thyroxine replacement therapy undergoing coronary artery bypass grafting had an increased mortality rate. We speculate that insufficient thyroid hormone replacement could partly play a role in this outcome.

Coronary collaterals during single-vessel coronary angioplasty: effects of nitroglycerin.

BACKGROUND: Although the protective role of collaterals in coronary artery disease (CAD) is well known, the influence of drugs on collateral function remains controversial. HYPOTHESIS: We aimed to investigate prospectively the prevalence of spontaneously visible and recruitable coronary collaterals in consecutive patients with single-vessel CAD and the effect of systemic administration of nitroglycerin on these types of collaterals during percutaneous transluminal coronary angioplasty (PTCA). METHODS: Ipsi- and contralateral coronary artery contrast injections were performed before and during PTCA. Simultaneously with balloon occlusion, we measured coronary artery occlusion pressure via the balloon catheter. All measurements were repeated after administration of 0.5 mg of nitroglycerin intravenously. RESULTS: Of 101 consecutive patients, 24% had spontaneously visible and 30% had recruitable collaterals. Contralateral collaterals were five times more frequent than ipsilateral collaterals. Presence of collaterals was highly associated with the degree of coronary stenosis. Coronary occlusion pressure was higher in patients with than in those without collaterals. Collaterals prevented pain and ischemia during PTCA, and in this respect spontaneously visible collaterals were more effective than recruitable collaterals. There was no effect of systemic administration of nitroglycerin on appearance or occlusion pressure of coronary collaterals. CONCLUSION: Coronary collaterals were found in more than half of patients with single-vessel CAD, as the prevalence of recruitable collaterals was slightly higher than that of spontaneously visible collaterals. Nitroglycerin did neither recruit nor augment coronary collaterals.

Enhanced external counterpulsation does not alter arterial stiffness in patients with angina.

BACKGROUND: Enhanced external counterpulsation (EECP) is a noninvasive treatment for angina that acutely augments diastolic pressure and reduces cardiac afterload. However, the mechanism of the sustained clinical benefit seen with this therapy is not known. HYPOTHESIS: The study aimed to determine whether EECP leads to an improvement in arterial stiffness. METHODS: In all, 22 men and 1 woman with angina (age 63.6 +/- 6.7 years, mean +/- SD) were studied prior to and after 35 h of EECP therapy over 7 weeks. We measured carotid-radial (C-R) pulse wave velocity (PWV), and aortic augmentation index (AI) was derived from radial and carotid artery waveforms using applanation tonometry. Seventeen patients underwent treadmill exercise testing before and after the 7 weeks of EECP. RESULTS: After EECP therapy, despite a significant improvement in treadmill exercise time and a reduction in systolic and diastolic blood pressures, there was no significant change in any arterial stiffness parameters: Mean C-R PWV was 8.4 +/- 0.8 m/s at baseline and 8.0 +/- 1.2 m/s after 7 weeks of EECP, mean change: -0.4, 95% confidence interval (CI): -1.0, + 0.2, p = 0.17. Mean radial-derived AI was 25.7 +/- 10.4% before and 24.6 +/- 10.8% after, mean change: +1.1%, 95% CI: -2.3, +4.5, p = 0.53. Median AI-carotid was 31.5% before and 28.7% after; median change: -0.5, interquartile range: -9.5, +3.5, p = 0.32. Nineteen patients returned for 6-month recordings; neither blood pressure nor arterial stiffness readings were significantly different from baseline. CONCLUSION: Enhanced external counterpulsation therapy does not significantly alter arterial stiffness. Other than an initial reduction in blood pressure, the sustained clinical benefit seen with this therapy is unlikely to be effected through alterations in arterial wall mechanical properties.

Arterial concentration of 99mTc-sestamibi at rest, during peak exercise and after dipyridamole infusion.

Tracers for myocardial perfusion imaging during stress should not only have high cardiac uptake but they should also have a fast blood clearance to prevent myocardial tracer uptake after the ischaemic stimulus. The present study characterize the early phase of the arterial (99m)Tc-sestamibi (MIBI) time-activity curve after venous bolus injection at rest, during peak exercise and after dipyridamole infusion. We included 11 patients undergoing angioplasty for one-vessel disease (rest study) and 20 patients evaluated for the detection of haemodynamic significant coronary stenoses by (99m)Tc-sestamibi single photon emission computed tomography (SPECT) using either bicycle exercise testing (10 patients) or standard dipyridamole testing (10 patients). Arterial blood samples of 1 ml were taken from the left femoral artery (rest study) or the right radial artery (exercise and dipyridamole studies) every 5 s during the first 5 min postinjection. In the exercise and the dipyridamole studies blood sampling were extended to include blood samples every 5 min 5-30 min postinjection. Peak MIBI concentration was lower and decrease in concentration slower after tracer injection during exercise than during dipyridamole stress testing. This may cause an underestimation of perfusion defects during exercise because of MIBI uptake after the ischaemic stimulus. The implications of the study not only refer to the choice of stress modality when using MIBI. This study also underlines the importance of considering early blood clearance in addition to regional myocardial tracerkinetic aspects such as myocardial extraction fraction when new tracers are introduced.

Randomized comparison of percutaneous coronary intervention with coronary artery bypass grafting in diabetic patients. 1-year results of the CARDia (Coronary Artery Revascularization in Diabetes) trial.

OBJECTIVES: The purpose of this study was to compare the safety and efficacy of percutaneous coronary intervention (PCI) with stenting against coronary artery bypass grafting (CABG) in patients with diabetes and symptomatic multivessel coronary artery disease. BACKGROUND: CABG is the established method of revascularization in patients with diabetes and multivessel coronary disease, but with advances in PCI, there is uncertainty whether CABG remains the preferred method of revascularization. METHODS: The primary outcome was a composite of all-cause mortality, myocardial infarction (MI), and stroke, and the main secondary outcome included the addition of repeat revascularization to the primary outcome events. A total of 510 diabetic patients with multivessel or complex single-vessel coronary disease from 24 centers were randomized to PCI plus stenting (and routine abciximab) or CABG. The primary comparison used a noninferiority method with the upper boundary of the 95% confidence interval (CI) not to exceed 1.3 to declare PCI noninferior. Bare-metal stents were used initially, but a switch to Cypher (sirolimus drug-eluting) stents (Cordis, Johnson & Johnson, Bridgewater, New Jersey) was made when these became available. RESULTS: At 1 year of follow-up, the composite rate of death, MI, and stroke was 10.5% in the CABG group and 13.0% in the PCI group (hazard ratio [HR]: 1.25, 95% CI: 0.75 to 2.09; p=0.39), all-cause mortality rates were 3.2% and 3.2%, and the rates of death, MI, stroke, or repeat revascularization were 11.3% and 19.3% (HR: 1.77, 95% CI: 1.11 to 2.82; p=0.02), respectively. When the patients who underwent CABG were compared with the subset of patients who received drug-eluting stents (69% of patients), the primary outcome rates were 12.4% and 11.6% (HR: 0.93, 95% CI: 0.51 to 1.71; p=0.82), respectively. CONCLUSIONS: The CARDia (Coronary Artery Revascularization in Diabetes) trial is the first randomized trial of coronary revascularization in diabetic patients, but the 1-year results did not show that PCI is noninferior to CABG. However, the CARDia trial did show that multivessel PCI is feasible in patients with diabetes, but longer-term follow-up and data from other trials will be needed to provide a more precise comparison of the efficacy of these 2 revascularization strategies. (The Coronary Artery Revascularisation in Diabetes trial; ISRCTN19872154).

Enhanced external counterpulsation for treatment of refractory angina pectoris.

OBJECTIVE: Enhanced external counterpulsation (EECP) is a noninvasive, well-tolerated treatment, effective for managing patients with refractory angina pectoris. The aim of this study was to evaluate the efficacy of EECP to relieve symptoms, to decrease myocardial ischaemia and to improve cardiac performance in patients with intractable angina, refractory to surgical and medical treatment. METHODS: Twenty-five patients (24 men and one woman, mean age 65 years) with persistent ischaemia notwithstanding optimal medical therapy or after interventional or surgical procedure, received EECP sessions for 35 h. Each patient underwent dobutamine stress echocardiography before and after treatment. We evaluated modifications in either cardiac systolic or diastolic function, and in wall motion score index. RESULTS: Eighty-four percent of patients showed an increase in at least one functional angina class. We did not observe any significant changes in fractional shortening and diastolic function. Thirty-six percent of patients had a reduction in the area of inducible ischaemia at dobutamine stress echocardiography after treatment. Unfortunately, because of the small sample size, we did not find any statistically significant difference. There was a trend showing that patients who benefited the most were those with the worst systolic function and with severely compromised segmental kinesis (P = NS). CONCLUSIONS: EECP is effective in relieving symptoms in patients with refractory angina and may reduce inducible ischaemia at dobutamine stress echocardiography, especially in patients with reduced systolic function and compromised segmental kinesis.

Preoperative haemoglobin concentration and mortality rate after coronary artery bypass surgery.

We did an observational study in 2059 patients undergoing coronary artery bypass surgery to assess the effect of haemoglobin concentration on in-hospital mortality. We noted that individuals with a preoperative haemoglobin concentration of 100 g/L or less had a five-fold higher in-hospital mortality rate after surgery than those with a higher haemoglobin concentration, despite having had blood transfusions or the pump primed with blood preoperatively as a routine precaution. Our findings suggest that a low haemoglobin concentration is a marker of disease severity or comorbidity that has a major effect on survival rate.