Myocardial perfusion reserve in adults with cyanotic congenital heart disease.
In patients with cyanotic congenital heart disease (CCHD), a right-to-left shunt results in systemic hypoxemia. Systemic hypoxemia incites a compensatory erythrocytosis, which increases whole blood viscosity. We considered that these changes might adversely influence myocardial perfusion in CCHD patients. Basal and hyperemic (intravenous dipyridamole) perfusion measurements were obtained with [13N]ammonia positron emission tomographic imaging in left (LV) and right (RV) ventricular and septal myocardium in 14 adults with CCHD [age: 34.1 yr (SD 6.5)]; hematocrit: 62.2% (SD 4.8)] and 10 healthy controls [age: 34.1 yr (SD 6.5)]. In patients, basal perfusion measurements were higher in LV [0.77 (SD 0.24) vs. 0.55 ml x min(-1) x g(-1) (SD 0.09), P < 0.02], septum [0.71 (SD 0.16) vs. 0.49 ml x min(-1) x g(-1) (SD 0.09), P < 0.001], and RV [0.77 (SD 0.30) vs. 0.38 ml x min(-1) x g(-1) (SD 0.09), P < 0.001]. However, basal measurements normalized for the rate-pressure product were similar to those of controls. Calculated oxygen delivery relative to rate-pressure product was higher in the patients [2.2 (SD 0.8) vs. 1.6 (SD 0.4) x 10(-5) ml O2 x min(-1) x g tissue(-1) x (beats x mmHg)(-1) in the LV, P < 0.05, and 2.0 (SD 0.7) vs. 1.4 (SD 0.3) x 10(-5) ml O2 x min(-1) x g tissue(-1) x (beats x mmHg)(-1) in the septum, P < 0.01]. Hyperemic perfusion measurements in CCHD patients did not differ from controls [LV, 1.67 (SD 0.60) vs. 1.95 ml x min(-1) x g(-1) (SD 0.46); septum, 1.44 (SD 0.56) vs. 1.98 ml x min(-1) x g(-1) (SD 0.69); RV, 1.56 (SD 0.56) vs. 1.65 ml x min(-1) x g(-1) (SD 0.64), P = not significant], and coronary vascular resistances were comparable [LV, 55 (SD 25) vs. 48 mmHg x ml(-1) x g x min (SD 16); septum, 67 (SD 35) vs. 50 mmHg x ml(-1) x g x min (SD 21); RV, 59 (SD 26) vs. 61 mmHg x ml(-1) x g x min (SD 27), P = not significant]. These findings suggest that adult CCHD patients have remodeling of the coronary circulation to compensate for the rheologic changes attending chronic hypoxemia.
Brunken
Richard C
RC
Dept. of Molecular and Medical Pharmacology, David Geffen School of Medicine at the University of California, Los Angeles, USA. brunker@ccf.org
Perloff
Joseph K
JK
Czernin
Johannes
J
Campisi
Roxana
R
Purcell
Susan
S
Miner
Pamela D
PD
Child
John S
JS
Schelbert
Heinrich R
HR
D000328:Adult; D000641:Ammonia; D001784:Blood Gas Analysis; D003326:Coronary Circulation / Q000502:physiology*; D005260:Female; D006330:Heart Defects, Congenital / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006940:Hyperemia / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D010477:Perfusion; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D014655:Vascular Resistance / Q000502:physiology
D019275:Radiopharmaceuticals; D000641:Ammonia