Facilitation of coronary spasm by propranolol in Prinzmetal's angina: fact or unproven extrapolation?

BACKGROUND: Alpha-adrenergic activation enhances coronary vascular tone; beta-blockade leaves alpha-adrenergic vasoconstriction unopposed. Whether beta-adrenergic blockade facilitates coronary spasm in patients with Prinzmetal's angina is unknown. METHODS: Using quantitative angiography, we evaluated the response of normal and narrowed coronary arteries to intravenous propranolol, a cold pressor test (an alpha-stimulus), and the combination of the two in 15 patients with Prinzmetal's (group 1) and in 19 with classic (group 2) angina. From measurements of heart rate, systemic and pulmonary arterial pressures, and left and right ventricular ejection times, we derived the tension-time index per minute as a measure of the oxygen need (O2 demand) of the whole heart. RESULTS: In group 1, cold invariably constricted normal and diseased vessels, and in two patients elicited spasm at sites of significant lesions; these changes did not correlate with those in O2 demand. In group 2, the vasomotor reaction of normal and narrowed vessels in response to cold correlated with the modifications in O2 demand. After propranolol administration, (1) in normal vessels in both groups, the baseline luminal diameter varied in parallel with the changes in myocardial O2 demand; (2) narrowings in group 1 patients invariably dilated and in group 2 the caliber varied according to changes in O2 demand; (3) during cold stimulation, luminal narrowing in group 1 varied in parallel with O2 demand, and, in group 2, vessels were uniformly constricted. CONCLUSION: These results do not support the facilitation of coronary spasm by propranolol in Prinzmetal's angina and support the hypothesis that the contractility of coronary vessels in patients with this form of angina is different from that in the classic form.

[A case of complete myocardial revascularization with different arterial grafts: right internal mammary artery, right gastroepiploic artery and inferior epigastric artery]. / Un caso di rivascolarizzazione miocardica completa mediante tre differenti condotti arteriosi: arteria mammaria interna destra, arteria gastroepiploica destra, arteria epigastrica inferiore.

It has been well established that the internal thoracic artery (ITA) is a good alternative to the saphenous vein as conduit for coronary artery bypass grafting because of superior early and late patency. Many surgeons now commonly use both ITAs for CABG and many have adopted complex grafting methods such as free ITA graft and sequential anastomosis; despite these techniques, it's not always possible to achieve complete revascularization with arterial conduits. More recently the right gastroepiploic artery (rGEA) and the inferior epigastric artery (IEA) have been used as alternative arterial conduits. The authors report the experience of a case of myocardial revascularization in a patient with angina not responsive to medical therapy, severe tri-vessel coronary artery disease, which had a previous total bilateral saphenectomy; the patient was also found to have a right fibrothorax. In the surgical strategy the authors considered that the bilateral use of mammary artery could have been the cause of the depressed respiratory function and that it was important to leave intact the left hemithorax; they therefore employed the rITA in the revascularization of the anterior descending (AD). To complete the revascularization they used the IEA for a marginal branch of the circumflex artery and the rGEA for the interventricular posterior artery, branch of the right coronary artery. In this fashion good early results were obtained with absence of perioperative complications with a good life expectancy.

Coronary angiographic features in 2,234 patients with clinical suspicion of coronary heart disease without modifiable risk factors.

Among 12,720 patients subjected to coronary angiography because of clinical suspicion of coronary heart disease, 2,234 (78% men and 22% women) were free from major modifiable coronary risk factors. They did not report alcohol consumption, use of antiplatelet or lipid lowering agents, oral contraceptives or sex hormones; there was no history of bilateral oophorectomy, smoking, diabetes mellitus, hypertension, or obesity; the ratio of total to high-density lipoprotein cholesterol was < or = 4.5. We examined lesions causing > or = 50% stenosis to total obliteration of the 3 great coronary arteries or of their major branches, and classified these patients as having single-, double-, or triple-vessel disease, or normal angiograms (no luminal irregularities). We related the extent of the coronary angiographic involvement to age and sex. From the fourth to the eighth decade of life: a) prevalence of normal angiography was significantly higher in women; b) percentage of cases with single-vessel disease was similar in both sexes and gradually reduced with aging; c) prevalence of double-vessel disease in women did not vary significantly, although a slight decline was seen at older ages; in men figures at the fifth and sixth decades were significantly greater than in women; d) percentages by decade of triple-vessel disease in males were 24, 34, 41, 49 and 57%, respectively; corresponding values in women were 11, 13, 15, 27 and 44% (p < 0.01 at each decade of age); with advances of age the sex gap in triple-vessel disease narrowed, but did not disappear. Thus, atherosclerosis tended with age to involve more vessels rather than more subjects in both genders, indicating that in the absence of modifiable coronary risk factors coronary vessels remained clearly susceptible to the influence of age, both in men and women. In these patients the feminine gender exerted a substantial protection that persisted for the entire span of life.

Coronary angiographic patterns in hypertensive compared with normotensive patients.

Patients in this study were assessed by coronary angiography because of classic effort angina and a positive exercise test. Of these patients, 320 had untreated primary hypertension and 320, similar in age and gender distribution, were normotensive. In all patients coronary angiography documented that at least one major epicardial branch was restricted by 50% or more. Prevalence of single- and double-vessel disease in the fourth and fifth decades of life was similar in the two populations and in both tended to decline with age. Prevalence of triple-vessel disease was also similar in the two populations in the fourth and fifth decades; in either population it rose with age and reached a peak at the seventh decade of life. The percentages of hypertensive patients in the sixth and seventh decades with triple-vessel disease was significantly (p less than 0.01) greater (40% and 50%, respectively) than the corresponding values in normotensive individuals (25% and 31%, respectively). The left main coronary artery was not significantly more involved in the high blood pressure group. Pressure was moderately and similarly raised at any age in hypertension; serum cholesterol and triglyceride levels, blood glucose, and smoking habits were comparable in the two populations. These results suggest that hypertension does not accelerate the appearance of significant coronary narrowing or multiple vessel involvement. Starting from the sixth decade, the natural age-related evolution of coronary disease seems to be aggravated in hypertensive subjects, as reflected by an augmented number of diseased vessels. This process is probably related to high blood pressure in itself; whether the severity of hypertension might also exert an influence is not deducible from this study.(ABSTRACT TRUNCATED AT 250 WORDS)

[Various clinical and vasomotor coronary responses to calcium block in mixed angina and Prinzmetal's angina, expression of various physiopathologic mechanisms]. / Differente risposta clinica e vasomotoria coronarica al calcio-blocco nell'angina mista e nell'angina tipo Prinzmetal, espressione di un diverso meccanismo fisiopatologico.

Impedance to flow due to coronary spasm is currently interpreted as the mechanism of Prinzmetal angina. Flow impedance, probably of vasomotor origin, superimposed on severe coronary stenosis is also viewed as the trigger for the spontaneous component of mixed angina. The major question that we attempted to answer in this study was whether mixed angina may be considered a variant of the Prinzmetal form, or a particular manifestation of the classic effort form. For these purposes we investigated the acute vasomotor response to calcium channel blockade (nifedipine 10 mg sl) of both significant (greater than 50%) stenotic lesions and of normal coronary vessels in 22 patients with mixed angina and in 14 patients with Prinzmetal angina, and correlated it with the clinical response to treatment (nifedipine 20 mg qid). Calcium channel blockade, in fact, is considered as a specific remedy in the presence of an altered coronary vasomotility. The clinical response was evaluated through ambulatory Holter monitorings of 48 hour duration, while on placebo, nifedipine and placebo again. In mixed angina an angiographic evaluation showed that the residual lumen diameter of significant lesions was unchanged in 2, enhanced in 11 and reduced in 9 patients after sl nifedipine; lumen variations from base line ranged from +1.5 to -1.3 mm. Acute stenosis widening or narrowing correlated closely with the efficacy or not of the treatment. In the Prinzmetal group the vast majority of the lesions had compliant portions which invariably responded with dilatation (the residual coronary lumen increased by an average of 69% of base line); 100% of patients in this group responded favourably to treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

[The flow-pressure relationship in coronary perfusion in myocardial hypertrophy in hypertension]. / Relazione flusso-pressione di perfusione coronarica nel miocardio ipertrofico dell'iperteso.

For any given perfusion pressure the difference between coronary autoregulated and maximally vasodilated flow represents the flow reserve. If hypertension and cardiac hypertrophy are present, the line of autoregulated flow becomes higher, and the pressure-flow relationship at maximal vasodilation less steep, due to the raised resistance. In these circumstances, flow reserve reduces and the point at which rest flow equals maximal achievable flow may be shifted to a higher perfusion pressure. Thus, flow would decline even if the perfusion pressure is lowered to normal. We tested this point in a setting of patients having chest pain and normal angiography of the left epicardial branches. Baseline flow (ml/min) from the great cardiac vein (thermodilution) was 142 +/- 13 in 9 normotensives (controls), 144 +/- 15 in 7 hypertensives (Group 1) with normal (114 +/- 11 g) left ventricular mass index and 188 +/- 17 in 8 hypertensives (Group 2) whose left ventricular mass (171 +/- 24 g) exceeded the mean +2 SD of normal. Coronary perfusion pressure was lowered in these patients by 5 mmHg every 5 minutes with a titrated nitroprusside infusion, taking as endpoints a perfusion pressure of 60 mmHg in the controls and of 70 mmHg in hypertensives. At endpoints, flow was similar to baseline in controls and Group 1. In Group 2 flow started to decline and myocardial oxygen extraction to slightly but significantly rise at perfusion pressure of from 90 to 80 mmHg; at the endpoint flow was reduced by 26% of baseline (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophysiological characteristics and outcome in patients with idiopathic right ventricular arrhythmia compared with arrhythmogenic right ventricular dysplasia.

BACKGROUND: Idiopathic right ventricular arrhythmias (IRVA) are responsive to medical and ablative treatment and have a benign prognosis. Arrhythmias caused by right ventricular dysplasia (ARVD) are refractory to treatment and may cause sudden death. It is difficult to distinguish between these two types of arrhythmia. OBJECTIVE: To differentiate patients with IRVA and ARVD by a conventional electrophysiological study. METHODS: 56 patients with a right ventricular arrhythmia were studied. They had no history or signs of any cardiac disease other than right ventricular dysplasia. They were classified as having IRVA (n = 41) or ARVD (n = 15) on the basis of family history, ECG characteristics, and various imaging techniques. They were further investigated by standard diagnostic electrophysiology. RESULTS: The two groups were clearly distinguished by the electrophysiological study in the following ways: inducibility of ventricular tachycardia by programmed electrical stimulation with ventricular extrastimuli (IRVA 3% v ARVD 93%, p < 0.0001); presence of more than one ECG morphology during tachycardia (IRVA 0% v ARVD 73%, p < 0.0001); and fragmented diastolic potentials during ventricular arrhythmia (IRVA 0% v ARVD 93%, p < 0.0001). Data from the clinical follow up in these patients supported the diagnosis derived from the electrophysiological study. CONCLUSIONS: Patients with IRVA or ARVD can be distinguished by specific electrophysiological criteria. A diagnosis of ARVD can be made reliably on the basis of clinical presentation, imaging techniques, and an electrophysiological study.

Use of a new diagnostic catheter for transradial internal mammary artery angiography early after minimally invasive coronary bypass.

We describe a new diagnostic catheter specifically designed for selective catheterization of the left internal mammary artery via the ipsilateral radial approach. We used this catheter to assess the patency of the distal mammary-left anterior descending coronary artery anastomosis in 30 consecutive patients early after minimally invasive direct coronary artery bypass grafting. The new catheter design allowed easy and fast engagement of the left internal mammary artery leading to optimal vessel opacification in all cases. Angiography revealed graft problems in seven (23.3%) patients, two of whom required anastomosis revision, surgical in one case and with PTCA in the other. No LIMA injury occurred as a result of selective catheterization. Patients with functionally normal anastomosis were discharged on the same day of the diagnostic procedure.