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Since the discovery of sildenafil in 1989 as a highly selective inhibitor of the phosphodiesterase type-5 (PDE-5) receptor, 2 additional PDE-5 inhibitors, tadalafil and vardenafil, have emerged as safe and effective treatments of erectile dysfunction (ED). Enzymes in the PDE family catalyze the hydrolysis of the intracellular signaling molecules cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which is the second messenger of nitric oxide (NO) and a principal mediator of smooth muscle relaxation and vasodilation. Sildenafil was initially introduced for clinical use as the result of extensive research on chemical agents targeting PDE-5 that might potentially be useful in the treatment of coronary heart disease. Erection is largely a hemodynamic event, which is regulated by vascular tone and blood flow balance in the penis. Endothelial dysfunction, an early component of atherosclerosis, may inhibit a vascular event such as erection and is rarely confined to the arteries supplying blood to the penis, but more likely occurs throughout the vascular bed. In addition to the effects of the NO-cGMP signaling pathway on cavernosal smooth muscle, clinical findings have suggested that vascular tone in the pulmonary, coronary, and other vascular tissues expressed by PDE-5 is also influenced by this signal transduction mechanism. This has led to the emergence of novel therapeutic indications for sildenafil over a range of cardiovascular conditions that are either well-established risk factors or comorbidities with ED. Recently, the U.S. Food and Drug Administration approved sildenafil as an orally active therapy for the treatment of primary pulmonary hypertension. The drug will be marketed under the trade name of Revatio, not Viagra, the name used for the ED indication. The approved dose for primary pulmonary hypertension is 20 mg 3 times daily.

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We investigated the accuracy of computed tomographic measurements of main pulmonary artery diameter (MPAD) and of MPAD/ascending aorta diameter (AAD) in predicting moderate or severe pulmonary hypertension in 190 patients with acute pulmonary embolism. A pulmonary artery systolic pressure of > or = 50 mm Hg measured by Doppler echocardiography was considered moderate or severe pulmonary hypertension. A MPAD of > 28.6 mm and a MPAD/AAD ratio of > or = 1.00 measured by computed tomography were considered abnormal. A MPAD of > 28.6 mm had a 75% sensitivity and specificity, a 52% positive predictive value, a 89% negative predictive value, a 3.0 likelihood ratio for a positive test, and a 0.33 likelihood ratio for a negative test in predicting moderate or severe pulmonary hypertension. A MPAD/AAD ratio of > or = 1.00 had a 59% sensitivity, a 82% specificity, a 55% positive predictive value, a 84% negative predictive value, a 3.3 likelihood ratio for a positive test, and a 0.50 likelihood ratio for a negative test.

We investigated prior to gastric bypass surgery the prevalence of left ventricular diastolic dysfunction (LVDD) by Doppler and tissue Doppler echocardiography in 14 obese women and in 6 obese men, mean age 45 years, with a mean body mass index of 49 ± 5 kg/m² who had nocturnal polysomnography for obstructive sleep apnea (OSA). The Doppler and tissue Doppler echocardiographic data were analyzed blindly without knowledge of the clinical characteristics or whether OSA was present or absent. Of 20 patients, 8 (40%) had no OSA, 4 (20%) had mild OSA, and 8 (40%) had moderate or severe OSA. Moderate or severe LVDD was present in 4 of 8 patients (50%) with moderate or severe OSA and in none of 12 patients (0%) with no or mild OSA (p < 0.01). Obese patients with moderate or severe OSA have a higher prevalence of moderate or severe LVDD than obese patients with no or mild OSA.

Coronary angiography was performed in 152 men and 163 women with diabetes mellitus, mean age 55 +/- 8 years, because of chest pain. Of 67 patients with 3-vessel or 4-vessel coronary artery disease (CAD), 17 (25%) were treated with diet alone, 29 (43%) with insulin, 18 (27%) with sulfonylureas, 12 (18%) with metformin, and 6 (9%) with thiazolidinediones. Of 76 patients with 2-vessel CAD, 20 (26%) were treated with diet alone, 36 (47%) with insulin, 21 (28%) with sulfonylureas, 21 (28%) with metformin, and 11 (14%) with thiazolidinediones. Of 40 patients with 1-vessel CAD, 15 (38%) were treated with diet alone, 11 (28%) with insulin, 8 (20%) with sulfonylureas, 12 (30%) with metformin, and 4 (10%) with thiazolidinediones. Of 132 patients with 0-vessel CAD, 18 (14%) were treated with diet alone, 21 (16%) with insulin, 7 (5%) with sulfonylureas, 75 (56%) with metformin, and 35 (26%) with thiazolidinediones. Cochran-Armitage trend tests were used to examine whether the use of treatment significantly increases or decreases as the number of arteries with CAD increases (P = 0.036 for diet alone; P< 0.0001 for insulin, for sulfonylureas, and for metformin; P = 0.002 for thiazolidinediones).