Aortic Cardiac Index Research Articles

Disappearance of the shunt and lower cardiac index during exercise in small, unrepaired ventricular septal defects.

Clinical studies have revealed decreased exercise capacity in adults with small, unrepaired ventricular septal defects. Increasing shunt ratio and growing incompetence of the aortic and pulmonary valve with retrograde flow during exercise have been proposed as reasons for the previously found reduced exercise parameters. With MRI, haemodynamic shunt properties were measured during exercise in ventricular septal defects. Patients with small, unrepaired ventricular septal defects and healthy peers were examined with MRI during exercise. Quantitative flow scans measured blood flow through ascending aorta and pulmonary artery. Scans were analysed post hoc where cardiac index, retrograde flows, and shunt ratio were determined. In total, 32 patients (26 ± 6 years) and 28 controls (27 ± 5 years) were included. The shunt ratio was 1.2 ± 0.2 at rest and decreased to 1.0 ± 0.2 at peak exercise, p < 0.01. Aortic cardiac index was lower at peak exercise in patients (7.5 ± 2 L/minute/m2) compared with controls (9.0±2L l/minute/m2), p<0.01. Aortic and pulmonary retrograde flow was larger in patients during exercise, p < 0.01. Positive correlation was demonstrated between aortic cardiac index at peak exercise and previously established exercise capacity for all patients (r = 0.5, p < 0.01). Small, unrepaired ventricular septal defects revealed declining shunt ratio with increasing exercise and lower aortic cardiac index. Patients demonstrated larger retrograde flow both through the pulmonary artery and the aorta during exercise compared with controls. In conclusion, adults with unrepaired ventricular septal defects redistribute blood flow during exercise probably secondary to a more fixed pulmonary vascular resistance compared with age-matched peers.

Diagnostic value of non-invasive cardiac output parameters in premature infants with patent ductus arteriosus

Objective To investigate the diagnostic value of non-invasive cardiac output parameters: cardiac index (CI) and minute distance (MD), in premature infants with patent ductus arteriosus (PDA) and determine the cut-off value. Methods Clinical data of 98 premature infants admitted to the neonatal intensive care unit from January 2015 to June 2015 were collected. These premature infants were divided into the treated PDA group (n=30), the untreated PDA group (n=28) and the normal premature group (n=40) based on the results of echocardiogram in the first three days after birth and the use of drugs. Non-invasive cardiac output parameters were measured in the first three days after birth. The data were analyzed by t test, analysis of variance and SNK-q test. The diagnostic value of CI and MD for PDA was analyzed by the receiver operating characteristic curve. Results By preliminary analysis of the ROC curve, CI and MD were the most representative parameters for the diagnosis of PDA which need to be treated clinically, we thus chose CI and MD in this study. The aortic and pulmonary arterial CI and MD in the treated PDA group were significantly higher than in the untreated PDA group and the normal premature group (all P 0.05). The cut-off value of the aortic CI and MD was 2.95 L/(min·m2) and 21.50 m/min, respectively, while that of the pulmonary arterial CI and MD was 4.55 L/(min·m2) and 26.50 m/min, respectively. The sensitivity and specificity of the combined aortic CI and MD for the treated PDA group were 0.90 and 0.82, and those of combined pulmonary arterial CI and MD were 0.87 and 0.82; and those of combined aortic and pulmonary arterial CI and MD were 0.80 and 0.88, respectively. Conclusions The non-invasive cardiac output parameters CI and MD have good diagnostic value for the PDA needing clinical treatment, and the combined use of the two parameters can improve specificity, and help formulate the early treatment strategy for premature infants with PDA. When aortic CI was ≥2.95 L/(min·m2) and MD was ≥ 21.50 m/min, a preliminary diagnosis of the PDA needing clinical treatment, can be made, and simultaneously when the pulmonary arterial CI was ≥ 4.55 L/(min·m2) and MD was ≥ 26.50 m/min, the arterial duct should be closed timely. Key words: hemodynamics; premature infants; PDA; non-invasive cardiac output parameters