Conditions for “coronary steal” with dipyridamole

ABSTRACTS

THE ROLE OF ALDOSTERONE AND ALDOSTERONE ANTAGONISTS IN CONGESTIVE HEART FAILURE IN INFANCY Barry Baylen MD, Greqory Johnson MD, Reqinald Tsana MBBS. Laxm; Srivastava PhD; Simuel Kaplan MD,-FACC, Univ: of Cincinnati. Cincinnati. Ohio The failure of infant; with severe congestive heart failure (CHF) and congenital heart disease (CHD) to respond to conventional diuretic therapy is a conrmon indication for surgical intervention. Secondary hyperaldosteronism may be a major complicating factor in these patients and may contribute to their lack of response to medical therapy. We measured serum aldosterone (ald) by radioimnunoassay (micro-technique) in 8 infants (age 4 days-9 mos) with CHF secondary to CHD and in 20 normal control infants. Mean ald of controls was 23 ng%, range 2.8-75.5, which is similar to normal values previously described. In contrast, ald was markedly increased ,(y;r;;;)in 6 of 8 infants with CHF (mean=322.5 ns%, range . Several patterns of response to digoxin and intramuscular furosemide were observed in our patients. The 2 infants with normal ald responded well as manifested by clinical improvement, increased urinary output and increased urinary Na to K ratio (Una/Uk). By contrast, in 5 of 6 patients with increased ald, response was poor as reflected by decreased post-furosemide urinarv outout and reversed Una/Uk in the bresence of clinical signs of-p&-sistent fluid retention and normal or low serum osmolalitv. The addition of an aldosterone antagonist to the medical reqimen of 4 of these oatients resulted in markedlv improved post-furosemibe diuresis and increa&d Una/Uk. As signs of CHF cleared, ald fell siqnificantlv (~c.01). Hyperaldosteronism can be easily recognized by-eialuat;on of clinical course and serum and urine electrolytes and osmolalities and can be confirmed by serum ald assay. The recognition and treatment of hyperaldosteronism is important for optimal medical management of these infants.

CONDITIONS FOR "CORONARY STEAL" WITH DIPYRIDAMOLE. Lewis C. Becker,MD,FACC.Johns Hopkins Hosoitol.&Iltimore. MD Coronary vosodilot& have-been advbcated fo; red&on of a&e myocardial infarctionsize.Dipyridomole,o potent coronary orteriolar dilator, increasesflow to &chemic myodardium after cbronary ligation in the dog when the other coronarv arteries are normal _ However, the situ&ion might be morkedlybifferent when stenoies are present in the other orteries.Accordingly, in 10 anesthetized dogs, the distal left anterior descending (LAD) artery, was ligated and screw occluders olaced on the oro$mal LAD and circumflex (LC) arteries to reduce peak reoctiv’e hyperemio b 38 to 67%; resting flow remained normal .Regionol myocordia r flow was measured with 8-10~ diameter rabiwctiv& microspheres 1 hour after I igation, before and after l-1.5 mg/kg dipyridamole IV;myocardial injury was estimated by ST elevation in epicardial ECG’s.Heart rate was maintained constant by atria1 pacing and blood pressure (BP) by methoxomine infusion.Despite constant BP, dipyridamole caused a decrease in mean flow in ischemic myocordium from .22+ .02 to .l&.Ol ml/min/g (SEM,p<.Ol) while mean ST segment elevation Zcreased from 30.4+4.9 to 58.0t7.4mV (p c.05). In non-ischemic myocardium flowincreased from 1 .20 to 1 .61 ml/ min/g,but a marked maldistribution between inner (I) and outer (0) wall appeared (l/O; 1 .OOt.O2 to 0.30+.06,p<.OOl). In a second group of 6 dogs given dipyridamole, inflow restriction by the screw occluders wos less severe.ln this group in contrast to the first,Flow to ischemic muscle increased (. 14 to .I9 ml/min/g) and ST elevotion declined (55.6+21.2 to 41.0+35..5, ~~0.05). Thus, a “corona~steal” (reducfion in collateral flow at constant BP) is seen after dipyridamole only when the coronary arteries supplying collateral vessels are significantly stenosed.ln this setting dipyridamole causes reduced collateral flow and increased ST elevation.When stenoses are absent, dipyridomole appears to improve collateral flow and lessen the extent of myocardial injury.Therefore, whether coronary dilators ore beneficial or detrimental after acute coronary ligation is dependent upon the degree of obstruction of other coronary vessels.

120

January 1976

The American Journal of CARDIOLOGY

CORONARY ARTERY DILATATIONS. THEIR INFLUENCE ON LEFT VENTRICULAR FUNCTION AND PROGNOSIS. Benjamin Befeler, MD, F.A.C.C., Juan !I. Aranda, "ID, Nabil El-Sherif, MD and Ralph Lazzara, MD. VAH/University of Miami School of Medicine, Miami, Florida. Fourteen adult male patients evaluated angiographically because of symptoms of ischemic heart disease, either angina pectoris (AP) or congestive heart failure (CHF) exhibited fusiform or saccular coronary arterv dilatations (CAD)or aneurysms. Analysis of seqmental and overall left ventricular function disclosed that all patients had left ventricular dysfunction (LVD), manifested bv either decreased ejection fraction or decreased segmental motion, regardless of the degree of coronary obstructive lesions (COL), which accompanied a given dilatation. Eight patients exhibited AP, five CHF and one both. Four were class II, 8 class III and 2 class IV. Nine patients had diffuse dilatations, 3 had saccular and 2 both. In 10, the right coronary artery was involved, in 7 the circumflex and in 3 the anterior descending. Nine patients underwent surgery, LV aneurysmectomy or aorta-coronary bypass or both. Three patients had no COL but exhibited segmental LVD corresponding to the area of CAD. LVD can be related to CDL or CAD. AP was present in patients with and without COL. The patients were followed from 6 to 48 months (average 28). Twelve are alive today. One died of GI bleedinq with similar lesions in the mesenteric artery system. Adult patients demonstrating CAD form a subset cf individuals with ischemic heart disease, with a course more benign than common obstructive coronary arteriosclerosis. CAD are capable of producing AP and segmental LVD with and without COL.

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