[Effect of intravenous nytroglicerin in hypertensive patients during and after open heart surgery (author's transl)].

The present study was performed to compare hemodynamic effect of intravenous Nitroglycerin (TNT i.v.) in 14 patients developing acute hypertension (Group I) and in 7 non hypertensives after open heart surgery (Group II). In all patients, m.a. 56.6 yrs, (10 mitral and/or aortic prosthetic valve replacements, 9 aorto-coronary bypass, 1 open mitral commissurotomy, 1 closure of atrial septal defect) TNT was infused at doses of 0.5, 1, 2 microgram X kg X min. and subsequently at 2 microgram X kg X min. after volume administration (2 + V.A.) to maintain right and left atrial pressure the same as control (P = N.S.). Mean arterial, right and left atrial pressures (MAP, RAP, LAP), cardiac frequency and index (CF, CI and systemic vascular resistance index (SVRI) were monitorized. TNT i.v. resulted in hypertensive patients (Group I) in reduction vs. control of: a) RAP (--20.17%) and LAP (--20.58%) at 0.5 microgram X kg X min. b) RAP (--26.13%), LAP (--27.50%), MAP (--19.94%) and CI (--12.98%) at 1 microgram X kg X X min. c) RAP (--22.47%), LAP (--26.89%), MAP (--24.68%), CI (--12.6%) and SVRI (--17.34%) at 2 microgram X kg X min. When RAP and LAP was maintained by volume administration TNT i.v. (2 microgram X kg X min.) resulted in an even greater increase in CI and a greater decrease in MAP and SVRI ((--22.04% and --24.88% respectively). No significant hemodynamic modification (P less than or equal to 0.05) were observed in non hypertensive patients (Group II) at all doses of TNT i.v. The results confirm a predominant venodilator effect of TNT at low doses and a good effect on arterial resistances at high doses in hypertensive patients. In view of previous reports of differing effects on ischemia TNT i.v. may be preferable to other vasodilator drugs for control of acute post-ECG hypertension, only on condition to maintain an adequate left ventricular filling pressure to prevent a fall of cardiac index. Moreover the absence of significant (P less than or equal to 0.05) hemodynamic modifications in non hypertensive patients may be a further advantage in the treatment of myocardial ischemia with i.v. TNT.