EFFECT OF NITROGLYCERIN IN PATIENTS WITH INCREASED PULMONARY VASCULAR-RESISTANCE UNDERGOING CARDIAC TRANSPLANTATION

Acute right ventricular failure due to persistent pulmonary hypertensi on is a risk factor for premature death after cardiac transplantation. The purpose of this study was to follow changes in pulmonary haemodyn amics in patients with pulmonary hypertension undergoing heart transpl antation, and to examine whether postoperative changes can be predicte d from a preoperative nitroglycerin (NTG) challenge. Seventeen consecu tive patients with NYHA class IV heart failure and pulmonary hypertens ion (pulmonal vascular resistance (PVR) >2.5 Wood units) underwent an NTG infusion before cardiac transplantation and were followed up using measurements of pulmonary haemodynamics before, early (24 h) and late (6 months) after cardiac transplantation. The effect of NTG was measu red preoperatively and compared with posttransplantation values. Posto perative (24 h) PVR was reduced in all patients when compared with pre operative findings (PVR from 4.1 +/- 0.2 to 1.9 +/- 0.2 Wood units, Me an +/- SEM, p < 0.05). Mean pulmonary artery pressure (mPAP) was lower ed in 16 of out 17 patients (41 +/- 2 to 26 +/- 1 mmHg, p < 0.05). Non e of the parameters were significantly changed during the subsequent 6 months. Postoperative PVR and mPAP were accurately estimated by preop erative NTG infusion (NTG vs 24 h posttranspl: PVR 2.2 +/- 0.2 vs 1.9 +/- 0.2 Wood units, p > 0.05; mPAP 30 +/- 2 vs 26 +/- 1 mmHg, p > 0.05 ). Heart transplantation candidates with pulmonary hypertension respon sive to NTG can be expected to obtain a postoperative immediate fall i n pulmonary pressures and PVR. The magnitude of this circulatory impro vement can be predicted from a preoperative NTG infusion and is not di fferent from values measured 6 months after transplantation.