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Improved right ventricular function following late pulmonary valve replacement for residual pulmonary insufficiency or stenosis.

Residual severe pulmonary insufficiency or stenosis may result in significant myocardial dysfunction late after repair of tetralogy of Fallot. Although pulmonary valve replacement has been advocated for selected patients, objective improvement in right ventricular function has been difficult to demonstrate. We undertook pulmonary valve replacement in 11 patients to treat residual insufficiency (n = 8) or stenosis (n = 3) and evaluated them before and after operation by radionuclide ventriculography and M-mode echocardiography. Patients' age at the original repair was 6.6 +/- 0.6 years (range 2 to 8 years) and at subsequent valve replacement was 14.6 +/- 1.5 years (range 5 to 20 years). Indications for pulmonary valve replacement were conduit stenosis indicated by a gradient greater than or equal to 75 mm Hg (n = 3), symptoms (n = 2), progressive cardiomegaly (n = 3), and new onset of tricuspid insufficiency (n = 3). Prior to pulmonary valve replacement, right ventricular ejection fraction was 0.29 +/- 0.12 (range 0.12 to 0.48) and rose to 0.35 +/- 0.10 (range 0.19 to 0.48) at a mean of 10.5 +/- 2.3 months after operation (p less than 0.05). Improvement (defined as an increase in ejection fraction greater than 0.05) was noted in seven patients whereas four demonstrated no change. Left ventricular ejection fraction before operation (0.55 +/- 0.12) was unchanged after pulmonary valve replacement (0.54 +/- 0.06). M-mode echocardiography demonstrated significant reduction in right ventricular dilatation. Right ventricular/left ventricular end-diastolic dimension fell from 1.03 +/- 0.30 to 0.73 +/- 0.13 after operation (p less than 0.01). Cardiothoracic ratio fell from 0.59 +/- 0.02 to 0.55 +/- 0.02 at a mean of 12 months after pulmonary valve replacement (p less than 0.01). Subjective improvement in exercise tolerance was noted in all seven patients who showed an increase in right ventricular ejection fraction. Of the remaining four patients, two had no improvement, one felt symptomatically improved, and one was too young for evaluation. These data demonstrate objective improvement in right ventricular function following pulmonary valve replacement and confirm the usefulness of this procedure in patients with significant right ventricular dysfunction secondary to residual pulmonary insufficiency and stenosis.

Adolescent↗

Right ventricular functional recovery after acute myocardial infarction: relation with left ventricular function and interventricular septum motion. GISSI-3 echo substudy.

OBJECTIVE: To evaluate the pattern of right ventricular (RV) functional recovery and its relation with left ventricular (LV) function and interventricular septal (IVS) motion in low risk patients after acute myocardial infarction (AMI). DESIGN AND SETTING: Multicentre clinical trial carried out in 47 Italian coronary care units. PATIENTS: 500 patients from the GISSI (Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico) -3 echo substudy, who underwent serial echocardiograms 24-48 hours after symptom onset and at discharge, six weeks, and six months after AMI. RESULTS: Tricuspid annular plane systolic excursion (TAPSE) increased significantly during follow up (mean (SD) 1.79 (0.46) cm at 24-48 hours to 1.92 (0.46) cm at six months, p < 0.001) and the increase was already significant at discharge (1.88 (0.47) cm, p < 0.001). LV ejection fraction (LVEF) was the best correlate of TAPSE at 24-48 hours (r = 0.15, p = 0.001). TAPSE increased significantly in patients both with reduced (< 45%) and with preserved (> or = 45%) LVEF, but the magnitude of increase was higher in patients with lower initial LVEF (p = 0.001). Improvement in IVS wall motion score index (IVS-WMSI) was the only independent predictor of TAPSE changes during follow up (r = -0.12, p = 0.007). CONCLUSIONS: In low risk patients after AMI, RV function recovered throughout six months of follow up and was already significant at discharge. TAPSE was significantly related to LVEF at 24-48 hours. The magnitude of RV functional recovery was higher in patients with lower initial LVEF. RV functional recovery is best related to IVS-WMSI improvement, suggesting that IVS motion has an important role in RV functional improvement in this setting.

Adult↗

Effects of vasopressin on right ventricular function in an experimental model of acute pulmonary hypertension.

OBJECTIVE: Arginine vasopressin is a promising systemic vasopressor in settings such as vasodilatory shock and cardiopulmonary resuscitation. The evidence that arginine vasopressin may also have a pulmonary vasodilatory effect makes it an attractive drug for the treatment of circulatory shock secondary to right ventricular failure and pulmonary hypertension. In the present study, we evaluated the effects of arginine vasopressin on right ventricular function and ventriculovascular coupling in the setting of moderate acute pulmonary hypertension and compared these effects with those of phenylephrine. DESIGN: Prospective laboratory investigation using an established model of acute pulmonary hypertension. SETTING: University hospital laboratory. SUBJECTS: Seven adult beagle dogs weighing 8-14 kg. INTERVENTIONS: After acute instrumentation to measure right ventricular pressure and volume with the conductance technique and pulmonary artery flow and pressure with high-fidelity transducers, the stable thromboxane analogue U46619 was infused continuously to obtain stable pulmonary hypertension. Phenylephrine and arginine vasopressin were administered consecutively in continuous infusions at doses titrated to achieve a 25% increase in aortic pressure. MEASUREMENTS AND MAIN RESULTS: Phenylephrine and arginine vasopressin both increased total pulmonary vascular resistance and arterial elastance without influencing characteristic impedance. Both drugs decreased cardiac output and stroke volume. Right ventricular hydraulic power output was reduced by arginine vasopressin but not by phenylephrine. Most importantly, arginine vasopressin caused a 31% decrease in right ventricular contractility measured as the slope of the preload recruitable stroke work relationship, whereas contractility was preserved during phenylephrine infusion. CONCLUSIONS: In the present model, arginine vasopressin causes pulmonary vascular constriction and exerts an important negative inotropic effect on the right ventricle. These findings suggest that one should be cautious in the use of arginine vasopressin when right ventricular function is compromised.

Acute Disease↗

Right ventricular function in systemic hypertension.

The aim of the study was the assessment of right ventricular (RV) structure and diastolic function in hypertensive subjects. The study group consisted of 44 patients with untreated, mild to moderate essential systemic hypertension. All the patients were in sinus rhythm, no symptoms of congestive heart failure, ischaemic or valvular heart disease and lung disorders were found. Twenty-six healthy subjects were the control group. M-mode echocardiographic measurements of the right ventricular wall (RVW) diastolic thickness, right ventricular outflow tract diameter (RVOTD), left ventricular (LV) structure and LV systolic function were performed. Pulsed Doppler echocardiography was used to measure peak early (TE) and peak atrial (TA) right ventricular diastolic filling velocities as well as velocity-time integrals (VTI-TE and VTI-TA). TE:TA and VTI-TE:VTI-TA ratios were calculated. Similar parameters of the left ventricular diastolic filling were recorded at the level of mitral annulus. Mean pulmonary artery pressure (MPAP) was measured non-invasively by the estimation of pulmonary artery systolic flows. We demonstrated in hypertensive patients significantly thicker RVW (3.94 vs 2.8 mm, P < 0.001) and increased LV mass. In the hypertensive, increased TA and VTI-TA and diminished TE:TA and VTI-TE:VTI-TA ratios were recorded, indicating the abnormalities of RV diastolic function. RV diastolic filling parameters correlated positively with corresponding parameters of LV filling. The results of our study demonstrate that impairment of LV diastolic function, the common finding in systemic hypertension, is associated with diastolic disturbances of the right ventricle. RVW thickening and hypertrophy of interventricular septum seem to be major factors influencing RV diastolic function.

Adult↗

Assessment of right ventricular function with Doppler echocardiographic indices derived from tricuspid annular motion: comparison with radionuclide angiography.

OBJECTIVE: To assess right ventricular systolic function using indices derived from tricuspid annular motion, and to compare the results with right ventricular ejection fraction (RVEF) calculated from radionuclide angiography. DESIGN: Pulsed Doppler echocardiography indices were obtained from 10 patients with a normal RVEF (group 1) and from 20 patients whose RVEF was less than 45% (group 2). RESULTS: The patients in the two groups were similar in age, systolic blood pressure, and heart rate. There was a close correlation between the tricuspid annular motion derived indices (D wave integral (DWI), peak velocity of D wave (PVDW), and tricuspid plane systolic excursion (TPSE)) and RVEF (r = 0.72, 0.82, and 0.79, respectively). DWI was significantly higher in group 1 than in group 2. PVDW discriminated adequately between individuals with abnormal and normal right ventricular ejection fraction. The sensitivity and specificity of tricuspid annular motion derived indices were very good. CONCLUSIONS: Indices derived from tricuspid annular motion appear to be important tools for assessing right ventricular systolic function.

Adult↗

[Right ventricular function in sleep apnea syndrome and chronic obstructive pulmonary disease].

The factors that contribute to the development of chronic cor pulmonale (CCP) in sleep apnea syndrome (SAS) are being continuously reviewed, as well as the role played by the coexistence of chronic obstructive pulmonary disease (COPD). Right ventricular function was evaluated in 20 SAS patients, 10 of whom presented associated (COPD). In all of them the following tests were performed while fasting: blood gasometry, spirometry, body mass index and isotopic ventriculography which included the determination of righ ventricular ejection fraction (RVEF). The RVEF of the group presenting COPD (mean +/- DS) (0.43 +/- 0.07) was not significantly different from the group without COPD (0.46 +/- 0.09). When the patients were regrouped according to the presence of hypoxemia during the day (paO2 less than 70 mmHg) a significant difference was evidenced between the mean value of the RVEF group with hypoxemia (n = 10) (0.40 +/- 0.02) and that of the group with normoxemia (n = 10) (0.50 +/- 0.09) (p less than 0.05). There were no statistically significant differences between the degree of obstruction and the BMI in either group. These results suggest that the worsening of RVF is more frequent in SAS patients who present daytime hypoxemia.

Adult↗

A new technique for the assessment of pulmonary regurgitation and its application to the assessment of right ventricular function before and after repair of tetralogy of Fallot.

Biplane right ventriculograms with simultaneous high fidelity pressure recordings were obtained in 24 patients with tetralogy of Fallot. Twelve patients were studied before repair and 12 were studied 67 (42) months after radical surgical repair without the use of a transannular patch. In the patients who had repair right ventricular end diastolic and end systolic volume indices were higher, and the ejection fraction was lower. Time to peak ventricular filling and the peak rate of ventricular fillings were also lower in this group and there was a significant relation between peak filling rate and ejection fraction. Postoperative pressure-volume loops from nine patients showed an increase in cavity volume during the decline in right ventricular pressure, which indicated pulmonary regurgitation. The mean regurgitant volume for the group correlated with end diastolic volume index, stroke volume index, and peak filling rate, but not with ejection fraction. These data show that both systolic and diastolic abnormalities of right ventricular function are detected in most patients after radical repair of tetralogy of Fallot. The reduction of ejection fraction previously reported in these patients is unrelated to the degree of pulmonary regurgitation and primarily reflects an impairment of contractile function that presumably is related to intraoperative events.

Blood Pressure↗

Effects of inhaled nitric oxide on right ventricular function in severe acute respiratory distress syndrome.

OBJECTIVE: To compare the effects of inhaled nitric oxide (NO) and an infusion of prostacyclin (PGI2) on right ventricular function in patients with severe acute respiratory distress syndrome (ARDS). DESIGN: Randomized prospective short-term study. SETTING: Post-surgical ICU in an university hospital. PATIENTS: 10 patients with severe ARDS referred to our hospital for intensive care. INTERVENTIONS: In random sequence the patients inhaled NO at a concentration of 18 parts per million (ppm) followed by 36 ppm, and received an intravenous infusion of PGI2 (4 ng.kg-1.min-1). MEASUREMENTS AND RESULTS: Inhalation of 18 ppm NO reduced the mean (+/- SE) pulmonary artery pressure (PAP) from 33 +/- 2 to 28 +/- 1 mmHg (p = 0.008), increased right ventricular ejection fraction (RVEF), as assessed by thermodilution technique, from 28 +/- 2 to 32 +/- 2% (p = 0.005), decreased right ventricular end-diastolic volume index from 114 +/- 6 to 103 +/- 8 ml.m-2 (p = 0.005) and right ventricular end-systolic volume index from 82 +/- 4 to 70 +/- 5 ml.m-2 (p = 0.009). Mean arterial pressure (MAP) and cardiac index (CI) did not change significantly. The effects of 36 ppm NO were not different from the effects of 18 ppm NO. Infusion of PGI2 reduced PAP from 34 +/- 2 to 30 +/- 2 mmHg (p = 0.02), increased RVEF from 29 +/- 2 to 32 +/- 2% (p = 0.02). Right ventricular end-diastolic and end-systolic volume indices did not change significantly. MAP decreased from 80 +/- 4 to 70 +/- 5 mmHg (p = 0.03), and CI increased from 4.0 +/- 0.5 to 4.5 +/- 0.5 l.min-1.m-2 (p = 0.02). CONCLUSIONS: Using a new approach to selective pulmonary vasodilation by inhalation of NO, we demonstrate in this group of ARDS patients that an increase in RVEF is not necessarily associated with a rise in CI. The increase in CI during PGI2 infusion is probably related to the systemic effect of this substance.

Administration, Inhalation↗

Right Ventricular function in aortic and mitral valve disease.

Radionuclide ventriculography of the right heart was performed in 56 patients within two weeks of cardiac catheterization using a gated first-pass technique. Thirteen patient served as normal controls, and 43 patients had severe aortic or mitral valve disease or both, 35 of whom subsequently underwent valve surgery. Right ventricular ejection fraction (RVEF) and the presence of central venous reflux was determined and related to catheterization findings. In normal patients, RVEF was 60 plus or minus 7 percent (mean plus or minus 1 SD). In patients with valvular disease, the RVEF was below the normal range in only 2/14 (14 per cent) when right ventricular peak systolic pressures were less than 50 mm Hg, compared with 16/29 (55 percent) with an RVEF below normal when right ventricular peak systolic pressures greater than 50 mm Hg (P less than .05). In contrast, there was no relation of right ventricular ejection fraction to ventricular filling pressure in valvular heart disease patients. There was no difference in early postoperative course in patients with normal or reduced ejection fraction. Central venous systolic reflux was not presented in normal patients, but was present in 3/12 (25 percent) and 22/25 (88 percent); P less than 0.1) of patients with right ventricular systolic pressures below and above 55 mm Hg, respectively, including all ten patients with documented tricuspid regurgitation. Radionuclide assessment of right ventricular function in patients with aortic or mitral valve disease or both provides information that cannot be inferred from right-sided pressure measurements.

Adult↗

Variability of right ventricular functional recovery after lung transplantation.

BACKGROUND: The purpose of this study was to assess by echocardiography the effects of lung transplantation on recovery of right ventricular (RV) function in patients with preoperative RV dysfunction. METHODS: Fourteen (20%) of 71 lung transplant recipients were identified by echocardiography as manifesting abnormal RV function before lung transplantation. These 14 patients were selected for follow-up echocardiographic study 8 months after transplantation. RESULTS: RV function improved significantly in the study group. Mean RV end-diastolic area decreased from 26.8 +/- 7.9 cm2 to 20.1 +/- 4.7 cm2 (P < 0.01); mean RV end-systolic area decreased from 21.5 +/- 6.8 cm2 to 13.1 +/- 4.2 (P < 0.01); and mean RV fractional area change (FAC) increased from 20.4 +/- 3.3% to 35.8 +/- 8.9% (P < 0.001). A subgroup of four patients, however, exhibited no change in RV function. Patients who achieved improvement in RV function tended to be younger, had shorter duration of disease before transplantation, and had higher pulmonary arterial (PA) pressures before transplantation (PA systolic, 89 +/- 28 mmHg vs. 38 +/- 11 mmHg, P < 0.001; PA diastolic, 42 +/- 11 mmHg vs. 19 +/- 3 mmHg, P < 0.002). Each of the eight patients with primary pulmonary hypertension exhibited improvement in RV function (mean delta FAC +20.6 +/- 5.9%), while two of three patients with emphysema and both patients with idiopathic pulmonary fibrosis failed to achieve improvement in RV function (mean delta FAC +2.3 +/- 1.2%). CONCLUSIONS: Improvement of RV function assessed by echocardiography occurs after lung transplantation, even in patients with severe preoperative RV dysfunction. However, the degree of improvement is variable and may depend on the degree of RV after-load reduction and the presence or absence of intrinsic myocardial disease. RV ejection parameters do not distinguish between these two possibilities.

Adolescent↗

Impact of preload and afterload on global and regional right ventricular function and pressure: a quantitative echocardiography study.

BACKGROUND: Several quantitative echocardiographic measures of global and regional right ventricular (RV) function have been proposed, but knowledge of the impact of increases in preload and afterload is limited. METHODS: Seventeen healthy participants were exposed to increased preload by rapid infusion of 30 mL/kg of saline over 15 minutes, and to increased afterload simulated in an 16- to 18-hour stay in a controlled hypoxic environment (fractional concentration of oxygen in inspired gas = 12.3%). Two-dimensional, Doppler, and Doppler tissue echocardiography evaluations were performed to evaluate global and regional RV function, with changes evaluated by paired analysis. RESULTS: Peak tricuspid regurgitation velocity increased in both conditions, whereas the RV end-diastolic diameter and acceleration time of the pulmonary forward flow only increased with increased preload and afterload, respectively. Estimates of RV function and contractility remained stable: no changes in the RV isovolumic acceleration (1.6 +/- 0.6 vs 1.6 +/- 0.4 and 1.3 +/- 0.4 cm/s2) or tricuspid annular plane systolic excursion (2.5 +/- 0.4 vs 2.5 +/- 0.3 and 2.6 +/- 0.3 cm) were seen (baseline compared with increased afterload and preload, respectively). The RV index of myocardial performance was increased with increased afterload (0.26 +/- 0.08 vs 0.34 +/- 0.13, P < .05), whereas no changes with increased preload were seen. Changes in loading conditions did not affect the regional strain. CONCLUSION: Moderate volume and pressure loading of the RV induces detectable changes in the RV pressure and morphology. Modern echocardiographic measures of systolic RV function seem stable with moderate increases in preload and afterload.

Adult↗

Does right ventricular function predict survival in patients with chronic obstructive lung disease?

Non-invasive measurements of the right ventricular ejection fraction by radionuclide ventriculography were made in 115 patients with chronic obstructive lung disease. Survival was assessed over a mean period of 918 days. The right ventricular ejection fraction was reasonably normal in most patients (mean 0.42, range 0.10-0.66) but was lower in those with peripheral oedema, indicating cor pulmonale (mean 0.31 (SD 0.07); p less than 0.0001). Right ventricular ejection fraction was related to survival, but the relationship was weak (p = 0.03) by comparison with the association between the arterial oxygen and carbon dioxide tensions and survival (both p less than 0.0001). It is concluded that, although right ventricular function is predictive of survival in patients with chronic obstructive lung disease, it is probably a reflection of severity of disease and does not directly affect the prognosis.

Adult↗

Right ventricular function in chronically anemic fetal lambs.

OBJECTIVE: Our purpose was to determine whether the increase in extravascular fluid in chronic fetal anemia occurs either because of heart failure or despite successful cardiac adaptation. STUDY DESIGN: Right ventricular function curves were obtained in five ovine fetuses at the start, midpoint, and end of 5 to 8 days of anemia induced by isovolemic daily hemorrhage. Least-squares fit of the ascending and plateau lines of stroke volume versus right atrial pressure were used to establish breakpoints (intersection of the ascending and plateau lines), which were compared by analysis of variance for repeated measures. Myocardial blood flow was measured by microspheres. RESULTS: Carotid arterial oxygen content was reduced from 7.0 +/- 0.3 to 2.1 +/- 0.1 ml/dl and the hematocrit from 29% +/- 1.8% to 13% +/- 0.6%. Breakpoint analysis of function curves showed that although right atrial pressure remained unchanged (3.4 +/- 0.7 and 3.6 +/- 0.6 mm Hg) stroke volume increased from 1.03 +/- 0.14 to 1.62 +/- 0.25 ml/kg. Both right and left ventricular coronary blood flow were increased, 1351 +/- 313 and 1166 +/- 264 ml/min per 100 gm. Excess fluid was present in abdomen and chest of most animals at autopsy. CONCLUSION: Tissue edema during severe anemia occurs despite normal right atrial pressure, increased stroke volume, and markedly increased coronary blood flow, markers of successful cardiac adaptation.

Anemia↗

Three echocardiographic methods in right ventricular function evaluation.

We employed two-dimensional echocardiography for the assessment of right ventricular (RV) volumes and/or function in a series of 44 patients. The results of three different echocardiographic approaches were compared with the data obtained from single-plane RV angiography following ultrasound within a 7-day interval. Only the echocardiographic area length method with two orthogonal imaging planes employed (apical 4-chamber and subcostal projections) yielded the beneficial results. The correlations between echocardiographic and angiographic RV volume estimates were rather high (end-diastolic volume: r = 0.83, end-systolic volume: r = 0.82, stroke volume: r = 0.81) and satisfactory in ejection fraction (r = 0.75). Using the method mentioned, the differentiation of patients with an angiographic evidence of RV failure (echocardiographic ejection fraction less than 0.55) from those without it was possible with a sensitivity of 0.68 and a specificity of 0.82. Concerning the clinical impact of the presented study, we can recommend the technique in question as a screening procedure for the detection of changes in RV function exceeding 12% (95% confidence limits).

Cineangiography↗

Resting right ventricular function in patients with coronary artery disease: pressure volume analysis using conductance catheters.

Right ventricular pressure volume cycles from patients with coronary artery disease were created in order to assess their characteristics and the effects of peak ventricular pressure and right and left artery coronary disease. Thirty-three patients undergoing diagnostic catheterisation for ischaemic heart disease underwent right ventricular catheterisation with a micromanometer and a conductance catheter. Simultaneous pressure and volume signals were recorded and analysed as functions of time, and of each other, forming pressure volume cycles. A total of 19/33 (58%) patients had an abnormal pressure volume loop with a clear end systolic shoulder, and an isovolumic relaxation phase. The mean peak ventricular pressure for all patients was raised (35.2 S.D. 11.8 mmHg), but there was no correlation between indices of shape and peak systolic pressure. Values of dP/dtmax were also raised, but there was no significant difference in this or any other index between patients with left or right coronary artery disease. Thus, in patients with coronary artery disease, the right ventricular pressure volume loop is frequently abnormal in a pattern that is recognised as a feature of an increased ventricular afterload.

Angina Pectoris↗

Comparison of left and right ventricular function in acute myocardial infarction.

Pulmonary arterial end-diastolic and mean right atrial pressures were compared in 25 patients with acute myocardial infarction and in one patient with unstable angina. No consistent relationship was observed between these pressures. Simultaneous ventricular function curves relating the stroke work of each ventricle to its respective filling pressure were constructed on 34 occasions, dextran infusion or diuresis being used to alter the filling pressure. The curves from each ventricle were described mathematically by a quadratic (parabolic) function as well as by a straight line function and then compared by canonical correlation analysis. Alterations in the left ventricular function curves occurred with and without depression or right ventricular function curves. These hemodynamic measurements demonstrate that acute myocardial infarction can alter the relationship between left and right ventricular function.

Adult↗

Postinfarction ventricular septal rupture: the importance of location of infarction and right ventricular function in determining survival.

Over a 5.5 year period, 1264 consecutive patients with acute myocardial infarction as confirmed by enzyme levels were prospectively identified. Of these, 25 (2%) suffered ventricular septal rupture (pulmonary/systemic flow range 1.5 to 6) 7 +/- 7 days after onset of myocardial infarction. Death occurred in 14 patients (56%) and was more common after inferior than anterior myocardial infarction (11 of 15 [73%] vs three of 10 [30%], p less than .05). Among 133 variables analyzed, survivors and nonsurvivors were similar with respect to all premorbid clinical characteristics, infarct size as assessed by peak creatine kinase values, shunt size, two-dimensional echocardiographic and hemodynamic indexes of left ventricular function, and extent of coronary disease. Compared with survivors, the nonsurvivors had greater impairment of right ventricular function as determined by a higher two-dimensional echocardiographically derived right ventricular wall motion index (RVWMI) (0.55 +/- 0.87 vs 1.70 +/- 0.45, p less than .001), greater elevation of right ventricular end-diastolic pressure (11 +/- 6 vs 17 +/- 6, p less than .02), and greater mean right atrial pressure (10 +/- 6 vs 16 +/- 3, p less than .01). Of interest, two of the three patients who presented with anterior myocardial infarction and who died had inferiorly extended infarcts and all had abnormal RVWMIs (greater than or equal to 1.0). As expected, cardiogenic shock shortly after onset of ventricular septal rupture was associated with a 91% mortality, but was more common after inferior than anterior myocardial infarction (60% vs 20%, p less than .05). The mean effective cardiac index was also higher in survivors than nonsurvivors (2.1 +/- 0.5 vs 1.2 +/- 0.5, p less than .001). Finally, multivariate analysis indicated that all nonsurvivors could be identified based on: an effective cardiac index of 1.75 liters/min/m2 or less, the presence of extensive right ventricular and septal dysfunction on the two-dimensional echocardiogram, a mean right atrial pressure of 12 mm Hg or more, and early onset of ventricular septal rupture. Thus, our data demonstrate that: mortality is higher when ventricular septal rupture complicates inferior than when it complicates anterior myocardial infarction, survivors can be distinguished from nonsurvivors and the prediction of outcome is highly accurate, and combined right ventricular and septal dysfunction has a substantial impact on prognosis.

Adult↗

Hypothermic low-flow cardiopulmonary bypass impairs pulmonary and right ventricular function more than circulatory arrest.

BACKGROUND: Hypothermic circulatory arrest (HCA) is used during surgical treatment of certain congenital heart defects. The possibility of ischemic neurologic injury associated with HCA has led some surgeons to use low-flow cardiopulmonary bypass (CPB) during the hypothermic interval (hypothermic low flow [HLF]). This study investigates the inflammatory response to HCA and HLF, and reports the consequences of this response on pulmonary and right ventricular function. METHODS: Piglets (3.1 to 6.6 kg) were cooled to 16 degrees to 18 degrees C using CPB, and randomized: HCA for 60 minutes (n = 7), or HLF (50 cc.kg(-1).min(-1)) for 60 minutes (n = 6). The piglets were rewarmed to 36 degrees C and weaned from CPB. Serum tumor necrosis factor-alpha (TNF-alpha) concentration, percent lung water, and pulmonary and cardiac function were measured before and after CPB. RESULTS: Tumor necrosis factor-alpha was higher after HLF (2,990.5 +/- 884.5 pg/mL), compared with HCA (347.6 +/- 89.2 pg/mL; p = 0.03). The percent lung water was higher after HLF (84.8% +/- 0.3%) than HCA (82.0% +/- 0.4%; p < 0.001). The alveolar to arterial oxygen gradient was worse after HLF (457 +/- 42 mm Hg) than HCA (285.8 +/- 45 mm Hg; p = 0.02). Pulmonary vascular resistance was greater after HLF (36.08 +/- 8.28 mm Hg.mL(-1).m(-2).min(-1)) than HCA (14.55 +/- 3.46 mm Hg. mL(-1).m(-2).min(-1); p = 0.049). The right ventricular pressure waveform peak derivative, corrected for systolic pulmonary artery pressure, was lower after HLF (14.1 +/- 1.4 sec(-1)), than HCA (23.8 +/- 2.7 sec(-1); p = 0.01). CONCLUSIONS: Hypothermic low flow extends exposure to CPB, and is associated with an increased inflammatory response compared with HCA. The greater inflammatory response after HLF may result in substantial nonneurologic morbidity in the postoperative period, demonstrated by pulmonary and right ventricular dysfunction. Interventions that attenuate the inflammatory response to CPB may prevent pulmonary and right ventricular dysfunction after HLF.

Animals↗