Predictive value of asymptomatic cervical bruit for carotid artery disease in coronary artery surgery revisited.

OBJECTIVE: To investigate the predictive value of asymptomatic cervical bruit for detecting internal carotid artery disease in consecutive patients undergoing coronary artery bypass grafting (CABG). DESIGN: A prospective cohort study. SETTING: Tertiary referral university hospitals. PATIENTS: 153 consecutive patients (mean age 57 years) undergoing CABG, without previous history of cerebrovascular events. INTERVENTIONS: Patients underwent detailed pre-operative work-up, including coronary angiography and carotid artery duplex scanning. Internal carotid artery diameter stenosis was graded as A: normal; B: < 15%; C: 15%-50%; D: 50-80%; D+: > 80-99% and E=complete occlusion. RESULTS: 72 patients (47.1%) (95% CI: 39%, 55%) had no evidence of internal carotid artery stenosis; 81 (52.9%) (95% CI: 44.9%, 60.9%) had varying grades of disease, unilateral or bilateral. Cervical bruit was detected in 12/153 patients (7.8%) (95% CI: 3.5%, 12.1%) of whom all but one (0.7%) had varying grades of internal carotid artery disease; of these, 4 patients had bilateral cervical bruit (2.6%) (95% CI: 0.06%, 5.2%). The sensitivity, specificity, positive and negative predictive values and overall accuracy of cervical bruit for detection of > or = 50% internal carotid artery stenosis were 23.5%, 95.8%, 25%, 95.5% and 91.8%, respectively. The relative risk of > or = 50% stenosis ipsilateral to cervical bruit in 306 sides was 5.58 (95% CI: 2.0, 15.0) and the odds ratio 7.1 (95% CI: 2.0, 25.0). CONCLUSIONS: Asymptomatic cervical bruit proved a highly specific clinical sign for detection of internal carotid artery stenosis, whether haemodynamically significant (> or = 50%) or otherwise, in patients undergoing myocardial revascularisation. This was matched by a high negative predictive value and overall accuracy for flow limiting atheroma (> or = 50% stenosis). Yet, steering carotid investigations on the basis of cervical bruit alone would result in > or = 80% internal carotid artery stenosis remaining undetected in 3% of overall patients, in whom cervical bruit is absent.

Nifedipine tablets for systemic hypertension: a study using continuous ambulatory intraarterial recording.

The action of nifedipine tablets was examined in 17 patients with essential hypertension focusing particularly on the profile of blood pressure (BP) reduction over 24 hours resulting from both twice-daily and once-daily therapy (dose range 40 to 120 mg daily). This new formulation of nifedipine has a more prolonged and lower peak plasma level than an equivalent dose of nifedipine capsules. Our patients were fully ambulant and studied by continuous intraarterial recording techniques. BP responses during isometric and dynamic exercise testing were also observed. Within-patient comparisons of consecutive mean hourly systolic and diastolic BP showed a highly significant effect from twice-daily therapy (p less than 0.001) for nearly the entire day. Also, significantly lower BP was maintained during isometric and dynamic exercise. Mean hourly heart rates were not significantly altered. The profile of action of the single morning dose was initially similar, but its efficacy diminished from 6 P.M. to 8 A.M. on the following day. Side effects were not unduly troublesome and did not cause any patient withdrawals. Four patients developed mild ankle edema. Two others had facial flushing. Nifedipine given twice daily in tablet form, therefore, is an effective antihypertensive drug capable of lowering BP consistently over 24 hours in ambulant patients and during formal exercise testing. We suggest that this agent may be useful as initial therapy for systemic hypertension, although the tablets are not as yet widely available.

Acute and chronic effects of sustained action buccal nitroglycerin in severe congestive heart failure.

Vasodilators, such as nitroglycerin, have been widely used in the treatment of acute and chronic heart failure for therapeutic manipulation of the venous and arterial circulations to improve left ventricular function. We have tested the efficacy of a new formulation for sustained release buccal delivery of nitroglycerin (biological life 5-6 hr) in 21 patients with severe congestive heart failure due to ischaemic cardiomyopathy using maximal treadmill exercise testing and radionuclide angiography. A single-blind placebo-controlled acute and an open chronic phase (4 weeks) of treatment were employed. The mean dose was 23.4 mg daily, and clinical assessment suggested significant improvement in 15 patients. The mean ejection fraction (placebo) of 14.1% +/- 1.6 SEM increased to 19.1% +/- 1.7 (acute) and to 21.6% +/- 1.7 (chronic treatment) (P less than 0.001; n = 16). The mean exercise time increased from 3.02 +/- 0.4 min (basal) to 5.95 +/- 0.6 min (chronic) (P less than 0.001). Segmental wall motion abnormality was shown to improve after treatment for 4 weeks. There were no major side effects. Nine patients were reassessed after 24 weeks on the same regimen; exercise time and left ventricular ejection fraction were similar to the 4-week period, thus demonstrating a sustained improvement in cardiac function and functional capacity. A worthwhile functional and objective haemodynamic improvement was demonstrated in these patients with severe chronic congestive heart failure. This mode of treatment may have useful therapeutic value in the management of patients with a wide range of ischaemic heart failure.

How should we investigate the arteriopath for coexisting lesions.

The surgical techniques dealing with patients suffering from chronic arterial disease were developed during the first era of vascular surgery. Computerised tomography and other non-invasive screening techniques which were developed in the middle years has resulted in improved selection of patients for arteriography and surgery and has provided better means for study of the natural history of the disease. Latterly increased sophistication of these techniques has enabled us to detect and accurately assess asymptomatic arterial disease and to follow its development in the cerebrovascular, peripheral and coronary arterial circulation. This has resulted in a better understanding of risk factors involved both in the presenting lesion and in the circulation in general. From the latter point of view since the surgical management of ischaemic heart disease has improved so dramatically in the last 15 years, it is felt that a greater degree of success should be obtained in patients undergoing peripheral vascular reconstructive surgery. It is suggested therefore that adequate evaluation of the cardiac and cerebrovascular status of patients suffering from peripheral vascular disease should help to improve the overall prognosis and it is the object of this paper to set out the ways and means in which this might be achieved.

Noninvasive detection of coronary artery disease in patients presenting with claudication.

ECG chest wall mapping with bicycle ergometry which can detect not only myocardial ischaemia but also individual coronary artery territories involved has been used to screen 100 consecutive patients presenting with claudication. Fifty-three had a positive history and/or evidence of ischaemic heart disease on a resting ECG. The test was positive in 38, negative in 38 and inconclusive in 24, the latter because of inadequate heart rate response. In 11 out of 38 (29%) with a positive test there was no history or evidence of myocardial ischaemia on a conventional resting ECG. ECG changes suggestive of three vessel coronary disease were found in three, single vessel coronary disease in 16 and two vessel disease in 19. Of the latter, eight had changes in the LAD/circumflex distribution, indicating left main stem or equivalent disease. These together with the three with triple vessel coronary disease constituted a subset of 11 (11%) high risk patients who merited coronary angiography with a view to confirming the presence of severe coronary disease.

The effect of enalapril on leg muscle blood flow in patients with claudication.

In the percent study the authors have demonstrated that the peripheral blood flow and resistance as measured by strain-gauge venous occlusion plethysmography were favourably altered by enalapril. The peripheral blood flow increased significantly and since there was no detectable change in ankle pressure this indicated a decrease in resistance during administration of the drug.

Prevalence and distribution of coronary disease in claudicants using 12-lead precordial stress electrocardiography.

AIMS: to evaluate the prevalence of coronary artery disease (CAD) by means of modified stress electrocardiography in patients presenting with intermittent claudication. METHODS: three hundred consecutive patients (188 male) with intermittent claudication (post-exercise ankle brachial index <0.8), and 100 age and sex-matched controls, were assessed for CAD with resting and stress 12-lead-precordial ECG. A history of angina and previous myocardial infarction (MI) was recorded. EXCLUSION CRITERIA: recent (<1 month) MI; unstable angina; prior coronary intervention; arrhythmias; conduction abnormalities; uncontrolled hypertension; heart failure, digoxin therapy, and inability to perform tests. RESULTS: based on antecedent angina, MI and abnormal resting ECG, CAD prevalence was 47% in claudicants and 6% in controls; on 12-lead-precordial ECG stress testing, CAD prevalence was 46% (95% CI: 40.1-51.7%) in claudicants and 11% (95% CI: 4.8-17.2%) in controls (both p <0.0001). Only 67% of claudicants (n=141) with antecedent angina, MI or an abnormal resting ECG, met the criteria of CAD on stress testing; also 28% of claudicants without antecedent angina, MI and a normal resting ECG (n=159) had evidence of CAD. The odds ratio for CAD in claudicants was 6.9. Based on 12-lead-precordial ECG stress testing we detected the presence of: one-, two- and three-vessel disease in 14.7% (95% CI: 10.6-18.7%), 19% (95% CI: 14.5-23.5%) and in 12.3% (95% CI: 8.6-16%) of claudicants; and in 8, 3 and 0% of controls, respectively. CONCLUSIONS: forty six percent of patients with intermittent claudication had concomitant CAD, and 31% two- or three-vessel disease. In the presence of claudication the odds ratio for CAD is 6.9 (95% CI: 3.5-13.4) and for two- or three-vessel disease 14.8. Non-invasive modified stress electrocardiography by enabling identification of those with multi-vessel CAD and thus by providing cardiac risk stratification may help bridge the gap between clinical evaluation and invasive coronary imaging.

Intermittent claudication as a manifestation of silent myocardial ischemia: a pilot study.

One hundred consecutive patients with intermittent claudication were screened noninvasively with electrocardiography chest wall mapping stress test and transcutaneous aortovelography during bicycle ergometry. Electrocardiographic chest wall stress testing indicated three-vessel coronary disease in 25 patients and left anterior descending plus circumflex (left main stem equivalent) disease in seven. In these 32 patients transcutaneous aortovelography demonstrated a decrease in stroke distance (an index of cardiac stroke volume) (median, -28%; 90% range, +5% to -48%), and coronary angiography confirmed the presence and severity of the disease. The claudication distance ranged between 50 and 250 meters. After myocardial revascularization or medical therapy a significant increase occurred in the stroke distance after exercise (median, +20; 90% range, +40% to -25%); also a significant increase in the postexercise pressure index and a reduction in the recovery time (p less than 0.01). No change occurred in the ankle/pressure index at rest. Twelve patients were able to walk without being limited by claudication; 15 reported improvement with a two to tenfold increase in claudication distance. No change occurred in three. The results indicate that silent myocardial ischemia is a common finding in patients with intermittent claudication. It produces left ventricular dysfunction and a decrease in stroke volume leading to a large fall in ankle pressure and early onset of claudication during exercise. Niltrates and myocardial revascularization tend to reverse this.