Differences in aerobic capacity evolution and cardiovascular risk factors between diabetic and non-diabetic patients at different stages of a cardiac rehabilitation

Introduction

Type 2 diabetes mellitus (DM) is an important factor that is associated with increased cardiovascular morbidity, producing disorders in different devices and systems whose mechanisms are not entirely known. This study was conducted in order to understand the evolution of aerobic capacity and the different cardiovascular risk factors (CVRF) in diabetic patients compared to non-diabetic patients.

Methodology

Prospective observational study. A total of 301 patients were included consecutively in a conventional cardiac rehabilitation program from January 2017 to March 2020, after one month of having had acute coronary syndrome, phase II of which lasted 2 months, who had an analysis, ergometry with spire gas analysis, and anthropometric characteristics were included. Those who had signs of ischemia in ergometry were excluded from the study. The tests were conducted as recommended by the ATS/ACCP.

Results

301 patients were included, with an average age of 57.6±9.1 years, diabetics 92 (30,6%), LVEF average 56.9±9.6%, women 13.6%. Among the basal characteristics, diabetic patients had the highest prevalence of dyslipemia (89.1% vs 68.4% p s <0.001), HTA (62% vs 47.8% p x 0.03) and lower FEVI (55.1±10.26 vs 57.8±8.9 p-0.03), in addition to lower peak oxygen consumption (VO2 ml/kg/min) (18.8±5.0 vs 22.9±6.3 p-<0.001); DM being an independent predictor to obtain a lower VO2 with an OR 1.25 [IC (95%) 1.31–1.19 p<0.001] (Table 1). At the end of Phase II, both groups gained better control of CVRF (Table 2) including an improvement in VO2; but in the DM group the gain rate was significantly lower (0.08±0.14 Vs 0.13±0.17 p=0.02). In phase III (average follow-up 7.3 months) the benefits in the control of CVRF (Table 2) were maintained in both groups with the highest rate of increase in VO2 in patients with DM (0.07±0.2 Vs 0.02±0.13 p=0.05) (Image 1).

Conclusions

In our study, patients with DM undergoing an RHC program achieve better control of FRCV and aerobic capacity in a similar way to non-diabetic patients, which is maintained at 7 months of follow-up in phase III, although initially the aerobic capacity gain in diabetics is slower, achieve a higher increase in VO2 in Phase III.

Funding Acknowledgement

Type of funding sources: None.

Is it feasible to predict maximal oxygen uptake without an ergoespirometry?

Introduction

To determine the aerobic capacity and the cardiopulmonary response to exercise is an important tool to assess functional capacity and a pronostic factor in patients with coronary artery disease (CAD). Maximal oxygen uptake (VO2) is considered the gold standard for measuring aerobic capacity, and a maximal graded exercise test is required for its direct measurement. Nevertheless, it requires long duration sessions, qualified medical personal and expensive equipment in order to perform it. These are the main reasons why its use is not widely spread in daily clinical practice and more accessible tests are needed. The aim of this study is to determine if we can predict the VO2 in patients with CAD, depending on basal characteristics of the patient.

Objective

To develop an equation to predict VO2 based on the 6-minute walk test (6MWT), basal characteristics and the presence of cardiovascular risk factors in patients with CAD and preserved left ventricular ejection fraction (LVEF).

Methods

We performed a cross-sectional prospective study with 202 patients with CAD and preserved LVEF, who were consecutively included in a conventional cardiac rehabilitation programme from March of 2019 to March of 2020 and underwent a 6-minute walk distance test and an ergoespirometry. The presence of cardiovascular risk factors, comorbidities and anthropometric variables were also evaluated. The tests were performed following ATS recommendations. The predictive equation for VO2 was obtained with a multivariate regression analysis. To assess the fit of the predictive model, we used conventional linear regression models according to the coefficient of determination (R2). A P value <0,05 was statistically significant.

Results

A total of 202 patients were analysed. The mean age was 57,5±9,3 years, mean LVEF was 61,2±6,14%, 13,4% were female, 54,4% arterial hypertension, 30,2% with diabetes, 76,7% dyslipidemia, 36,1% obese, 6,4% with peripheric artery disease, 9,4% with pulmonary disease. Correlations of the mentioned characteristics and the 6MWT with VO2 were statistically significant (p<0,001). Objectively measured VO2 had a significant correlation with age, gender, type II diabetes mellitus, BMI and 6MWT. Multiple regression analysis revealed the following VO2 prediction equation: 32,590-[2,784x gender (0=male/1=female)]-(0,177x age)-(2,756x DM (0=ausence/1= presence)]+(0,027x6MWT)-(0,468xBMI). There was acceptable correlation between measured and predicted VO2 max (R2=0,6). There were not stadistically significant differences between measured VO2 max by ergoespirometry and predicted VO2 max by our equation (22,52±5,82 vs 23,02±4,28, p=0,057).

Conclusions

Our study provides an VO2 prediction equation based on the demographical characteristics, the presence of cardiovascular risk factors and the results in the 6MWT in patients with CAD, which might be used as an alternative in the case of unavailability of an ergoespirometry.

Funding Acknowledgement

Type of funding sources: None.

[A simplified method of continuous-wave Doppler noninvasive assessment of ventricular relaxation in mitral insufficiency]

INTRODUCTION AND OBJECTIVES

The minimum value of dP/dT is a parameter of diastolic function that can be estimated noninvasively by analyzing the profile of velocity of the mitral regurgitant jet, recorded by continuous-wave Doppler. This estimation requires a complex analysis of the curves that impedes its practical use. Our objective was to validate a simplified method to estimate noninvasively the value of dP/dTmin when mitral regurgitation exists. We calculated the pendient of the profile of velocity of the curve of mitral regurgitation during its deceleration, between 3 and 1.5 m/s, an interval that defines a difference in pressure using the formula delta p = (4v2(1) - 4v2(2)). We divided this interval by the time needed by the jet to decelerate from 3 to 1.5 m/s, obtaining the rate of pressure decay, in mmHg/s.

METHODS

We provoked mitral regurgitation in five pigs and registered dP/dT and the curve velocity of mitral regurgitation simultaneously, by micromanometer-tipped catheter and continuous-wave Doppler, respectively. The rate of pressure decay was calculated on the mitral regurgitation curve.

RESULTS

We obtained 29 simultaneous registers. The coefficient for the correlationship between dP/dT and the rate of pressure decay was with an r value of 0.62 (p < 0.0001). The rate of pressure decay underestimated systematically the value of dP/dT. Intra and interobserver variability of TDP was 9 and 11%, respectively.

CONCLUSIONS

This study validates a simplified method to estimate dP/dT noninvasively, with acceptable correlation with invasive measurements and adequate reproducibility.

[Penetrating trauma by foreign body in the left heart ventricle]

We present the case of a patient who suffered a cardiac penetrating trauma due to a 6-cm long steel splinter. He was self-admitted to the emergency room and was asymptomatic. Cardiac trauma was diagnosed by the presence of a foreign body in his chest X-ray. Transthoracic and transesophageal echocardiography showed pericardial effusion and a dense foreign body that crossed the left ventricle from upside down and forward to back. The patient underwent cardiac surgery under extracorporal circulation. A shooting wound was seen on the left ventricular free wall. Transesophageal echocardiography was performed during surgery in order to define the position of the foreign body and to discard lesions due to multidirectional injury. Lesions were repaired and the patient was discharged with no complications. This case report illustrates the possibility of survival after cardiac penetrating trauma, and the role of echocardiography in the diagnosis and surgical repair of this type of trauma.