Transcatheter aortic valve implantation: technical aspects, results and indications.

The development of the percutaneous heart valve (PHV) may become a primary therapeutic modality for the high risk and inoperable patients with critical symptomatic aortic stenosis. The first human percutaneous aortic valve implant was performed by our group in April 2002. To date, more than 500 Cribier-Edwards-PHV have been implanted worldwide using arterial trans-femoral or trans-apical approach. Data on the retrograde transfemoral approach is growing with more than 270 patients implanted as of October 2007. Procedural success rate is high (86%) and the 30-day mortality is 12%. Today, 2 patients are alive at a follow-up of more than 4 years. The same Cribier-Edwards-PHV can be implanted using trans-apical approach. In this procedure, PHV is introduced under direct vision into the left ventricle via a mini-thoracotomy. This obviates the concerns regarding vascular access in the presence of small caliber vessels and/or vascular occlusive disease. More than 200 patients have been treated with this approach. In the European experience 30-day mortality is 14%. There is intense interest in PHV technology, and there are multiple devices at various stages of development in animals and humans. The most developed is the CoreValve Revalving Technology. More than 350 patients have been treated with this technique. The immediate and mid-term results with this device are promising with a procedural success of 92% and a 30-day mortality of 15%. The future of this technology and its application is dependent on the continued collaboration between general internists, cardiologists, surgeons, engineers, and industry.

Right ventricular ischemia in patients with primary pulmonary hypertension.

OBJECTIVES: The goal of this study was to determine whether right ventricular (RV) ischemia is a contributory factor in the development of RV dysfunction in patients with primary pulmonary hypertension (PPH). BACKGROUND: Patients with advanced PPH develop RV dysfunction, characterized by a decreased cardiac output, increased right atrial pressure (RAP) and/or elevated RV end-diastolic pressure, which progresses to heart failure and death. The cause of this dysfunction is unknown. Right ventricular ischemia may play a role in its development. METHODS: From 1992 to 1999, a prospective study involving 23 patients with PPH at the Instituto Nacional de Cardiologia "Ignacio Chavez" (Mexico City, Mexico) was undertaken. These patients were evaluated clinically and further studied by echocardiography, right heart catheterization and stress myocardial scintigraphy using technetium 99m sestamibi. RESULTS: Nine patients of 23 were found to have scintigraphic images consistent with RV ischemia. Significant correlation was found between RV ischemia obtained through myocardial perfusion scintigraphy and elevation of RV end-diastolic pressure (p < 0.001), elevation of RAP (p < 0.037) and a decrease in mixed venous oxygen saturation (p < 0.0001). No other clinical or hemodynamic variables showed a significant correlation with RV ischemia. CONCLUSIONS: A direct correlation exists between RV ischemia, as determined by myocardial scintigraphy, and hemodynamic alterations suggestive of RV dysfunction in patients with PPH.

Treatment with beta-adrenergic blocking agents after myocardial infarction: from randomized trials to clinical practice.

OBJECTIVES: Our aim was to determine the percent of patients with myocardial infarction who are treated with beta-adrenergic blocking agents in dosages proved to be effective in preventing death after a heart attack. BACKGROUND: In the prospective randomized trials showing that beta-blocker treatment improves survival rates after myocardial infarction, relatively high dosages of these agents were used. However, it is not known whether these dosages are used in current clinical practice. METHODS: In a retrospective analysis of clinical data from 606 consecutive survivors of myocardial infarction at four university hospitals in three countries, we assessed the number of infarct survivors receiving prospectively defined "effective dosages" of beta-blockers. We defined these dosages as those that demonstrated improved survival rates of infarct survivors who received active drug in large, prospective, double-blind, placebo-controlled trials. RESULTS: Only 58% of infarct survivors with no contraindications to beta-blockers received these drugs at the time of hospital discharge, and only 11% received dosages equivalent to > 50% of the effective dosages. Independent predictors of failure to prescribe beta-blockers to infarct survivors without contraindications to these drugs were the use of diuretic agents, transient heart failure, impaired left ventricular function and increased patient age. Among patients receiving beta-blockers, only the use of propranolol predicted prescription of a low beta-blocker dosage. CONCLUSIONS: Failure to prescribe beta-blockers after myocardial infarction is common but in most cases is not due to clear contraindications. Many patients not receiving beta-blockers belong to subgroups that would derive the greatest benefit from such treatment. Finally, even when beta-blockers are prescribed, the dosages used are considerably lower than those proved to be effective in preventing death after myocardial infarction.

Risks of anticoagulant therapy in pregnant women with artificial heart valves.

In an attempt to identify the best treatment for pregnant women with cardiac-valve prostheses who are receiving oral anticoagulants, we studied 72 pregnancies prospectively. In 23 pregnancies (Group I), the coumarin derivative acenocoumarol was discontinued and the patients received 5,000 U of subcutaneous heparin every 12 hours from the 6th to the 12th week of gestation, in 12 pregnancies (Group II), heparin was not substituted for the coumarin derivative until after the 7th week, and in 37 pregnancies, detected after the first trimester (Group III), the coumarin derivative was given throughout gestation. In most patients heparin was again substituted for the oral anticoagulant after the 38th week. Three mothers had thrombosis of a tilting-disk mitral prosthesis (two cases were fatal) during heparin treatment. No differences were found in the rates of spontaneous abortion in the three groups. Coumarin embryopathy occurred in 25 percent and 29.6 percent of the pregnancies in Groups II and III, respectively. We conclude that in the second and third trimesters of pregnancy, coumarin derivatives provide effective protection against thromboembolism while causing few fetopathic effects, but that these agents are contraindicated from the 6th to the 12th weeks of gestation. Low-dose heparin does not protect against prosthetic-valve thrombosis, and the possibility that a larger dose might be more effective requires further exploration.

Mycobacterium fortuitum endocarditis after mitral valve replacement with a bovine prosthesis.

We have described a patient who had mitral valve replacement with a bovine prosthesis, followed by infectious endocarditis caused by Mycobacterium fortuitum. We found no previous reports of endocarditis caused by this organism involving a biologic heart prosthesis.

[Response of normal children to the treadmill exercise test using the Bruce protocol]. / Respuesta de los niños sanos a la prueba de esfuerzo en banda sinfin con el protocolo de Bruce.

Fifty nine boys and 41 girls underwent exercise stress testing (ETT), utilizing the Bruce protocol. Their mean age was 10 years. They were grouped by sex, age and body surface area. Blood pressure (BP), heart rate (HR) at rest, during exercise and after were monitored as well as the duration of the test and the energy cost. The HR and-BP had a similar linear relationship in both groups during the different stages of the test. The duration of the test expressed in minutes was 11.8 +/- 1.2 in boys and 10.7 +/- 1.2 in girls (P = 0.001). The oxygen consumption (ML/kg/min) was 45.2 +/- 4.9 and 41.9 +/- 4.5 that is equivalent to 12.9 +/- 1.4 and 11.9 +/- 1.2 mets for each group respectively. The group of boys of 6 (9.8) and 14 years of age (13.6) (P = 0.002) and in the girls in the 7 (9.5) and 10 years age group (11.8) P = 0.05. We conclude that 1) The ETT can be done in children safely but was have to take in consideration their age, sex, and body surface area in evaluating the results. 2) This study gives a reference to evaluate children with an without heart disease.

The problem of cardiac valve prostheses, anticoagulants, and pregnancy.

To assess the maternal and fetal risks in patients with cardiac valve prostheses, a series of 223 pregnancies in 156 women was studied. In 68 pregnancies (group I) treatment with antiplatelet agents was substituted for that with coumarinics from the first trimester on. Group II (128 pregnancies) received coumarinics through the thirty-eighth week of gestation. Three patients in group I died as a result of thrombosis of their caged-ball valves. The incidence of cerebral embolism was 25.0% in group I and 2.3% in group II patients, while that of spontaneous abortion was 10.3% and 28.1%, respectively. Coumarin embryopathy was found in 7.9% of group II infants. Fetal death did not occur in the 12 cases in which subcutaneous heparin was substituted for the coumarin derivative in the first trimester and the last 2 weeks of pregnancy (group III), but maternal cerebral embolism developed in 8.3% of the patients. Finally, uneventful pregnancies and deliveries were observed in 12 of 15 mothers (group IV) with biological prostheses who received no anticoagulants. It is concluded that (1) women with cardiac valve prostheses should be counseled against becoming pregnant, (2) antiplatelet agents do not provide protection against thromboembolism in these patients, (3) because of the high incidence of fetal death and birth defects use of coumarinics is contraindicated in the first trimester and the last weeks of pregnancy, (4) the substitution of heparin at these times may decrease the incidence of these complications, and (5) bioprostheses are indicated in women who wish to bear children.

[Arterial hypertension. Considerations on its current status in Mexico. In memory of Samuel Zajarias]. / Hipertensión arterial. Consideraciones sobre su estado actual en México. A la memoria de Samuel Zajarias.

The present article summarises statistical information about the problem of hypertension in this country making reference to international and national epidemiological works, with the purpose of evaluating the problem in community. Includes information about the clino-pathologic experience acheived at the National Institute of Cardiology of Mexico. The data is analyzed and commented from the point of view of how worth might be to study hypertension in Mexico.