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The activity of the enzyme methylenetetrahydrofolate reductase (MTHFR) determines homocysteine (Hcy) levels, and polymorphisms in its gene affect the activity of the enzyme. Changes in the enzyme's activity may lead to a higher susceptibility to develop arterial and venous thromboembolic disease. The aim was to analyze the relationship between the C677T and A1298C polymorphisms of MTHFR, Hcy levels, and prothrombotic biomarkers in pulmonary embolism (PE) and acute myocardial ischemia (AMI). Clinical files of patients with thromboembolic diseases having complete data and whose doctor had requested an assay to determine the polymorphisms of the MTHFR gene, Hcy levels, and prothrombotic biomarkers were studied to search for the correlation between mutations of the MTHFR gene and Hcy levels in the different diseases. We included 334 files: 158 were from women and 176 from men (51 [19 SD] years). Sixty-three percent have had thrombosis, 8% AMI, and 31% PE. Patients with thrombosis had elevated frequency of the C677T polymorphism. The CC genotype was higher than the TT genotype ( P = .003) and CT versus the TT ( P = .009). In patients with PE, the CC genotype was higher than the TT genotype ( P = .038). Pulmonary embolism with massive and submassive events had predominant genotypes 677 TT ( P = .003) and the AA 1298 ( P = .017). Elevated Hcy levels in the presence of the T allele in the C677T gene and of the A allele in the A1298C gene are associated with AMI and massive and submassive PE.

BackgroundDown's syndrome (DS) is a genetic anomaly, which undergoes increased morbidity and mortality when associated with congenital heart disease (CHD). The aims of the study were to determine the prevalence of CHD and pulmonary hypertension (PH) in DS.MethodsOne hundred twenty-seven patients with DS living in Mexico City were evaluated by physical exam, electrocardiogram and echocardiogram.ResultsCHD was found in 40%. In 80% (n = 102) PH was present [systolic pulmonary artery pressure (SPAP) of 47 ± 19 mm Hg and mean pulmonary artery pressure (MPAP) of 32 ± 11 mm Hg]. Patients with CHD and PH were classified as having 1) no shunt (n = 18) with SPAP of 37 ± 9 mm Hg and MPAP of 25 ± 6 mm Hg and 2) with shunt (n = 26) with PASP of 57 ± 29 mm Hg and MPAP of 38 ± 19 mm Hg (p ≤ 0.001). In those without CHD or with CHD without shunt (n = 76), SPAP was 37 ± 19 mm Hg and the MPAP 25 ± 6 mm Hg. The prevalence of PH in DS was 5.9% at one year and 15% at 10 years. The odds ratio of PH in DS with CHD was 7.3 vs. 3 without CHD.ConclusionDS has a high prevalence of CHD and PH. PH prevalence increases when it is associated with CHD. The pathophysiology of PH in DS without CHD should be studied in the near future. Echocardiography is an indispensible tool for evaluation of DS.

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SUMMARY Hydralazine was administered acutely to 12 patients who had pulmonary arterial hypertension of unknown cause. All of the patients were studied at rest and nine during exercise. On the basis of hydralazine response at rest, the patients were divided in two groups. In six patients (group A), pulmonary arteriolar resistance (Rp) decreased from 8.4 ± 1.4 to 4.8 ± 1.4 U/in (p < 0.001), cardiac index (CI) increased from 3.47 i 0.3 to 5.86 ± 0.5 1/min/m' (p < 0.005) and systemic resistance (Rs) decreased from 25 4 to 14 ± 2 U/mi (p < 0.01). The Rp/Rs ratio did not change significantly after hydralazine (0.32 ± 0.03 vs 0.33 ± 0.07, NS). In the other six patients (group B), Rs decreased from 25 ± 2 to 17.0 ± 1 U/mi (p < 0.01), but the other variables did not change significantly. Our results suggest that the pulmonary vasodilatory effect of hydralazine caused a marked reduction in right ventricular afterload in group A. In group B, a marked systemic vasodilatory effect occurred and right ventricular afterload was not reduced. On the basis of the previous hemodynamic response, only group A patients were treated with oral hydralazine (50 mg every 6 hours). Hemodynamic measurements were repeated 48 hours after hydralazine, both at rest and during exercise, as well as 8 months later in five of the six patients in whom the beneficial hemodynamic effects persisted. These data suggest that hydralazine can reduce Rp in selected patients (pulmonary arterial pressure < 60 mm Hg, Rp < 15 U/Mi and Rp/Rs ratio < 0.7) with pulmonary hypertension of unknown cause.