Echocardiographic predictors of an adverse response to a nifedipine trial in primary pulmonary hypertension - Diminished left ventricular size and leftward ventricular septal bowing

Background: The clinical course in primary pulmonary hypertension (PPH) is improved by calcium channel blocker therapy in those with a favorable hemod ynamic response during a trial of high-dose oral nifedipine. Although trial s of nifedipine are performed only in patients who demonstrate pulmonary va sodilator reserve to short-acting agents, this response does not predict th e safety of nifedipine treatment, which can result in severe first-dose hyp otension and death. Study objectives: To identify echocardiographic parameters that predict fir st-dose nifedipine-induced hypotension in patients with PPH. Methods: The pretrial echocardiograms of 23 consecutive PPH patients (mean age, 42.3 +/- 13 years; 77% female) undergoing evaluation of pulmonary vaso dilator reserve with nifedipine mere analyzed. Patients were classified as those who suffered first-dose nifedipine hypotension (group I) and those wh o did not (group 2). Echocardiographic measures of chamber size and septal geometry in the two groups were compared. Results: Five measures reflecting diminished left ventricular (LV) size and leftward ventricular septal bowing were found to be associated with nifedi pine hypotension: LV transverse diameter in systole (LVDs; p = 0.007), LV t ransverse diameter in diastole (LVD; p = 0.05), LV area in systole (LVAs; p = 0.009), LV area in diastole (LVAd; p = 0.03), the ratio of RV to LVAs (p = 0.02), and leftward ventricular septal bowing (p = 0.01). The LV dimensi ons found to best predict nifedipine-induced hypotension were LVDs <2.7 cm, LVDd < 4.0 cm, LVAs < 15.5 cm(2), and LVAd < 20.0 cm(2). Conclusions: Readily available echocardiographic parameters in patients wit h PPH are predictive of nifedipine-induced hypotension, and can be used to select patients in whom a trial of nifedipine should be avoided.