[Percutaneous implantation of an aortic prosthetic valve on a degenerated mitral bioprosthesis. Report of one case]

Reintervention of a mitral degenerated bioprosthesis has a high surgical risk, especially in elderly patients with multiple comorbidities. We report a 74 years old female with two previous cardiac surgical procedures and a new structural mitral bioprosthesis deterioration with severe mitral regurgitation. Considering her high-surgical risk, a fully percutaneous treatment was performed with a balloon-expandable aortic valve in mitral position (valve-in-valve) through a transseptal approach with a favorable outcome. This technique is an attractive and effective option with a relatively low rate of complications that could solve this challenging and complex disease.

[Balloon pulmonary angioplasty for the treatment of chronic thromboembolic pulmonary hypertension]

BACKGROUND

Balloon pulmonary angioplasty (BPA) is a therapeutic alternative for patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH).

AIM

To report the initial experience with the "refined BPA technique" with the use of intravascular images.

PATIENTS AND METHODS

Between June 2015 and June 2016 we selected fourteen patients with CTEPH who were considered candidates for BPA. Lesions targeted for treatment were further analyzed using intravascular imaging with optical frequency domain imaging (OFDI). We report the immediate hemodynamic results and four weeks of follow-up of the first eight patients of this series.

RESULTS

We performed 16 BPA in eight patients aged 61 ± 14 years (88% women). Mean pulmonary artery pressure (PAPm) was 48.6 ± 5.8 mmHg. Success was achieved in seven patients (88%). A mean of 2.3 segments per patient were intervened in 11 sessions (1.6 sessions/ patient). Only one patient developed lung reperfusion injury. No mortality was associated with the procedure. After the last BPA session, PAPm decreased to 37.4 ± 8.6 mmHg (p=0.02). Pulmonary vascular resistance (RVP) decreased from 858,6 ± 377,0 at baseline to 516,6 ± 323,3 Dynes/sec/cm-5 (p<0.01) and the cardiac index increased from 2.4±0.6 at baseline to 2.8±0.3 L/min/m2 (p=0.01). At 4 weeks after the last BPA, WHO functional class improved from 3.3±0.5 to 2.5±0.5 (p<0,01) and six minutes walking distance from 331±92 to 451±149 m (p=0.01).

CONCLUSIONS

BPA guided by OFDI for the treatment of inoperable CTEPH patients is a safe alternative with excellent immediate hemodynamic and clinical results.

[Survival of patients with pulmonary arterial hypertension after the advent of specific pulmonary vasodilator therapies]

BACKGROUND

Pulmonary arterial hypertension (PAH) is a rare and progressive disease. Long-term survival remains poor despite of advances in specific vasodilator therapy.

AIM

To describe the survival rate in a cohort of PAH patients in two referral centers in Chile.

PATIENTS AND METHODS

One hundred fifteen patients aged 43 ± 15.6 years (85% females) with PAH qualified for this study. Their median pulmonary artery pressure was 55.4 ± 14 mmHg and their six minutes walking capacity was 368 ± 119 m. They were followed for 58 ± 0.4 months and their actual survival rates were compared with the estimated survival using the equation proposed by the French registry of PAH.

RESULTS

One, two and three year survival rates were 97, 94 and 89%, respectively. The observed survival rates were greater than the estimated survival.

CONCLUSIONS

The improvement in survival rates observed in this cohort of patients is similar to what has been described in literature.

Prevalence of seven cardiovascular-related genetic polymorphisms in a Chilean mestizo healthy population

OBJECTIVE

Among the genetic factors associated with cardiovascular disease (CVD), determining polymorphic genotypes could help to understand the appearance of the illness. Ethnic differences in these polymorphisms could explain population variability in susceptibility to CVD. The main goal of this research is to study the presence of more relevant genetic variants of ApoE, CETP, ACE, PAI-1, MTHFR, FII and FVL of the coagulation cascade, to describe the presence of cardiovascular-related variants in a mestizo group of the Chilean people.

METHODS AND RESULTS

The studied population comprised 146 unrelated subjects from the general population, diagnosed as healthy, who were genotyped through conventional and/or real-time PCR. The allele frequencies for the Chilean population were: Apo E, ε2: 0.036, ε3: 0.875 and ε4: 0.089; CETP, B1: 0.51 and B2: 0.49; MTHFR, C: 0.52 and T: 0.48; ACE, I: 0.603 and D: 0.397; PAI-1, 4G: 0.381 and 5G: 0.619; FII, G: 0.97 and A: 0.03, and FV Leiden, G: 0.97 and A: 0.03.

CONCLUSIONS

This study contributes to establish a first picture in the Chilean mestizo population about the frequencies of these variants, which could act as single or complementary risk factors to trigger CVD. The obtained allele frequencies show great differences in relation to other South American populations.

[Contemporary practice of the coronary angioplasty in Chile. Final report of the Chilean National Coronary Angioplasty Registry (RENAC) 2001-2002]

BACKGROUND

Coronary angioplasty was introduced in Chile in 1982, but only after the introduction of stents it became commonplace. However the results of this procedure at the national level remain largely unknown.

AIM

To assess the results and characteristics of coronary angioplasty and develop a national registry in Chile (RENAC).

PATIENTS AND METHODS

All centers performing angioplasty were invited to contribute prospectively with the clinical, angiographic, procedural characteristics and results of all consecutive coronary angioplasty procedures attempted between June 2001 and October 2002.

RESULTS

In 10 centers, 1768 lesions were treated in 1484 procedures (22.98% in women). Mean age was 60.8 +/- 11.3 years old. Diabetes was found in 21.8%, hypertension in 60.2%, dyslipidemia in 52.0%, active smoking in 40.0%, renal failure in 6.2%. Myocardial infarction was recent in 28.4% and acute in 19.7%. Forty eight percent of patients had unstable angina and 15.5% had stable angina. Fifty three percent of patients had single vessel disease and 71%, normal left ventricular eyection fraction. One vessel was treated in 90.6% of patients and 81.7% of lesions were treated with stents, 17.9% only with baloon and in 0.4% with atherectomy. Angiographic success was obtained in 95.2%. Clinical success was obtained in 92.2%, and 95.1% In patients without acute myocardial infarction. Overall inhospital death was 2.2%. In patients without myocardial infarction, the figure was 1.1%.

CONCLUSIONS

Coronary angioplasty in Chile is performed mostly for the treatment of acute coronary syndromes. Stents are the most frequently used devices. The high success, low mortality and complications observed are comparable to North American registries.

[Measurement of maximal oxygen uptake in a Chilean population sample]

BACKGROUND

Maximal oxygen uptake is considered by the International Biological Programme as the international standard of cardiorespiratory adequacy and physical condition.

AIM

To measure maximal oxygen uptake in normal Chilean subjects, to establish normal reference values.

SUBJECTS AND METHODS

Maximal oxygen uptake was measured in 2,203 subjects (451 women) aged 7 to 66 years old, during maximal exercise in a cyclo-ergometer or treadmill. This sample included trained sportsmen.

RESULTS

Maximal oxygen uptake in men was 3.4 +/- 0.8 Vmin (range 1.1 to 5.6) or 55.2 +/- 9.2 ml/kg/min (range 23.8 to 83.2). In women, the figures were 2.55 +/- 0.55 l/min (range 0.87 to 3.82) or 47.5 +/- 8.0 ml/kg/min (range 20.8 to 76.3). These values decrease 0.65 ml/kg/min per year of age.

CONCLUSIONS

These values can be useful as a normal reference for epidemiological, clinical or sportive purposes.

Maximal oxygen uptake in Chilean workers of normal nutritional status

Maximum oxygen uptake (VO2max) was measured directly and predicted from cardiac frequency measurements in 54 healthy Chilean industrial workers aged 20 to 55 years, together with assessment of their dietary intake, body composition and blood chemistry. Measurement of VO2 was performed on a motor-driven treadmill. The predicted VO2max was obtained using a cycle ergometer by two methods: 1) the Astrand-Ryhming nomogram and 2) the linear relationship between "steady state" heart rate (HR) and submaximum work, with subsequent extrapolation to "maximum" heart rate. Extrapolation of the HR/load regression line to 170 bpm permitted determination of the physical working capacity at 170 bpm (W170). VO2max for the 20-29 year group (Group I) averaged 3624 ml.min-1 and decreased to 3066 ml.min-1 in the 50-55 year group (Group IV). Lower values were obtained using the Astrand-Ryhming nomogram and HR/load regression (-15% and -9% respectively). W170 was also affected by age (Group I: 190.6 W and Group IV: 158.5 W). No significant correlation were found between VO2max and plasma variables, with the exception of cholesterol (r = 0.59). On the contrary, anthropometric variables showed significant correlations with VO2max, which permitted the prediction of VO2max using multiple regression equations. The two best correlations were: 1. VO2max = 0.800 - 0.0225.(A) +0.0189.(W)+1.26.(H) (r = 0.87; p less than 0.001) 2. VO2max = 0.996 - 0.0176.(A) + 0.025.(W) + 0.838.(H) + 0.0255.(LBM) (r = 0.88; p less than 0.001) where A = years of age; W = body weight in kg; H = height in m and LBM = lean body mass in kg.

Genetic ecology of hypertension

1. A comparative study has been made of a population genetically homogeneous living in two adjacent but strongly different ecosystems.

2. Individuals were ‘marked’ with common serologic major genes.

3. The predominant strength of the environmental factors was demonstrated by the observation that when maintaining the genetic factor constant, hypertension appeared in the more advanced (‘acculturated’) Lowland populations.

4. The absence of hypertension was confirmed in Highland isolated primitive peoples.

5. Blood pressure correlation between relatives varied significantly with changing ecosystems.

6. The predominant strength of heredity was nevertheless demonstrated by the fact that in acculturated populations the genetic component of variance was found to be greater than the environmental one, and the dominant component accounted for nearly half the genetic variance.

7. Hypertension appears in the Lowlands to be exclusively associated with some specific genotypes of the Rhesus and MN systems.

8. The determination of blood pressure may be controlled by few major genes operating in given ecosystems under the permissiveness of environmental agents.

Endemic goiter in Pedregoso (Chile). 1. Description and function studies

A survey on goiter was carried out in Pedregoso, an isolated Indian Reservation in the Chilean Andes. A palpable goitre was present in 84 per cent of the adult population. All subjects were clinically euthyroid and had a normal contraction time of the Achilles tendon reflex. The mean value for serum PBI was 5.06 μg/100 ml, with 22% of the cases having values below 4 μg. Iodine deficiency was established by its low concentration in drinking water (0.35 μg/liter) and in the urine (33 μg/24 h).

Radioiodine studies showed an average thyroid uptake of 68% at 24 h with a tendency to increase directly with thyroid size and to decrease with age. Serum labelled PBI reflected different radioiodine turnover rates, highest values being more frequent in large nodular goitres. Triiodothyronine (T3) suppression tests were negative in about one-third of the goitrous subjects. Perchlorate tests and antithyroid antibodies determinations consistently gave negative results.

Thyroxine (T4) was always the main labelled compound, T3 being significantly present in 9 out of 22 cases. Up to 18% of the circulating radioiodine at 48 h was not butanol-extractable, and appeared in the initial fraction of column chromatography analysis. Six out of 58 cases also showed endogenously labelled diiodotyrosine (DIT), which constituted up to 10% of the total circulating radioiodine at 48 h. After intravenous injection of a tracer dose labelled DIT, 5.8 per cent ± 0.51 of the dose was excreted unchanged in the urine within 2 h. The highest values were observed in the largest goitres.

The extra-thyroid organic iodine compartment was investigated after the injection of labelled T4 and T3. An increase in fractional turnover rate was always observed associated with an increase in the thyroxine distribution space.