Factors determining normalization of pulmonary vascular resistance following successful balloon mitral valvotomy

Acute and short term effects of successful mitral valvuloplasty on net atrio ventricular compliance and its correlation with clinical outcome

Aim of the study

Patients undergoing successful balloon mitral valvuloplasty (BMV) have variable improvement in New York Heart Association (NYHA) functional class (FC), exercise capacity (EC) and regression of systolic pulmonary artery pressure (sPAP). Improvement in net atrioventricular compliance (Cn), one of the major determinants of above factors is not routinely assessed. Aim of present study was to assess the change in Cn after successful BMV and its correlation with above factors.

Methods

50 patients of very severe mitral stenosis in sinus rhythm who underwent successful BMV have been studied. NYHA FC, 6 min walk test (6 MWT) and echocardiographic evaluation was done 24 h before and at 2 weeks, 12 weeks and 24 weeks after BMV. Echocardiographic parameters of patients with improvement in NYHA class of ≥2 (group A) were also compared with those with improvement in NYHA class of ≤1 (group B).

Results

Following successful BMV, there was progressive improvement in Cn upto 12 weeks with no further significant improvement till 24 weeks. Change in Cn showed very good correlation with change in NYHA class [r = 0.62, p < 0.01], 6 MWT [r = 0.30, p0.03] and regression of sPAP assessed at 12 weeks and was maintained upto 24 weeks. Change in MVA did not show any correlation with above factors. Group B patients had significantly lower Cn post BMV as compared to group A patients inspite of comparable MVA and trans valvular gradients.

Conclusion

Improvement in Cn following BMV has good correlation with clinical improvement. So Cn should also be assessed along with MVA to better predict clinical outcome.

Net atrioventricular compliance can predict persistent pulmonary artery hypertension after percutaneous mitral balloon commissurotomy

Background

Pulmonary hypertension is a common complication of rheumatic mitral stenosis (MS). Patients with similar mitral valve (MV) areas may have different pulmonary artery pressures. Net atrioventricular compliance (Cn) was found to play an important role in the development of pulmonary hypertension.

Aim

To test the value of Cn in predicting persistent pulmonary artery hypertension (PPAH) after percutaneous mitral balloon commissurotomy (PMBC).

Patients and Methods

Eighty patients with severe MS, suitable for PMBC were included in the study. We excluded patients with contraindication to PMBC, atrial fibrillation, failure of PMBC, and restenosis. All patients had undergone electrocardiography, echocardiography with measurement of MV area, systolic pulmonary artery pressure (SPAP), and Cn, PMBC, and follow-up echocardiography.

Results

Patients were divided into two groups: Group I: Cn < 4.2 mL/mmHg (36 patients), Group II: Cn ≥ 4.2 mL/mmHg (44 patients). Group I patients had significantly higher SPAP, and significantly lower SPAP reduction. Sensitivity of Cn < 4.2 mL/mmHg in prediction of PPAH was 88.9%, specificity was 88.6%, and accuracy was 88.8%. Independent predictors for PPAH were baseline Cn (p = 0.0027), and Cn improvement after PMBC (p = 0.0085). There was a significant negative correlation between Cn and baseline SPAP (r = −0.349, p = 0.0015), and a significant positive correlation between Cn and percent SPAP reduction (r = 0.617, p < 0.00001).

Conclusion

Measuring Cn can predict PPAH in MS patients after PMBC. It also may add value in evaluating MS patients undergoing PMBC and may help in predicting their prognosis.

Net atrioventricular compliance is an independent predictor of cardiovascular death in mitral stenosis

OBJECTIVES

Rheumatic mitral stenosis (MS) is a progressive disease, and risk of death may persist despite relief of the obstruction. Net atrioventricular compliance (C_n) modulates the overall haemodynamic burden of the MS and may be useful in predicting cardiovascular death after percutaneous mitral valvuloplasty (PMV).

METHODS

A total of 427 patients (mean age 50±16 years, 84% female) with severe MS undergoing PMV were enrolled. Doppler-derived C_n was estimated at baseline using a previously validated equation. The primary endpoint was late cardiovascular death, and the secondary endpoint was a composite of all-cause mortality, mitral valve (MV) replacement or repeat PMV over a median follow-up of 31 months (IQR: 7.8-49.2 months).

RESULTS

At baseline, 209 patients (49%) were in New York Heart Association (NYHA) functional class III or IV. During follow-up, 49 patients died (41 cardiovascular deaths), 50 underwent MV replacement and 12 required repeat PMV, with an overall incidence of cardiac mortality and adverse events of 4.1 deaths and 11.1 events per 100 patient-years, respectively. Low baseline C_n was a strong predictor of both cardiac death (adjusted HR 0.70, 95% CI 0.49 to 0.86) and composite endpoint (adjusted HR 0.81, 95% CI 0.67 to 0.91) after adjusting for clinical factors, baseline pulmonary artery pressure, tricuspid regurgitation severity, right ventricular function and immediate procedural haemodynamic data. The inclusion of C_n in a model with conventional parameters resulted in improvement in 5-year cardiovascular mortality risk prediction.

CONCLUSIONS

Baseline C_n is a strong predictor of cardiovascular death in patients with MS undergoing PMV, independent of other prognostic markers of decreased survival in MS, including baseline patient characteristics and postprocedural data. C_n assessment therefore has potential value in evaluation of cardiovascular mortality risk in the setting of MS.

Reversal of abnormal cardiac parameters following mitral valve replacement for severe mitral stenosis in relation to pulmonary artery pressure: A retrospective study of noninvasive parameters - Early and late pattern

BACKGROUND AND OBJECTIVES

Although the regression of pulmonary hypertension (PH) in mitral stenosis (MS) has been studied over varying periods postintervention, corresponding studies on the cardiac chamber alterations after surgery are very limited. We sought to determine the degree of reversal of these and the clinical status in connection with that of pulmonary artery pressures (PAPs) in the early and late postoperative periods.

METHODS

The preoperative, early, and 1-year postoperative data - functional class (FC), cardiothoracic ratio (CTR) in chest X-ray (CXR), and echocardiographically left atrium (LA), right atrium (RA), right ventricle (RV), left ventricle (LV), and pulmonary artery (PA) dimensions, PAP, tricuspid regurgitation (TR) - of 50 patients who had mitral valve replacement (MVR) for MS with PH were retrospectively analyzed for correlations with PAP (Pearson's), and their change (t-test), in relation to that in PAP. PH group-based [Group (Gp)-I PAP ≤60 mmHg, Gp-II PAP >60 mmHg] analysis highlighted the differences.

RESULTS

All parameters significantly correlated with the baseline PAP (p < 0.05), except LA (r = 0.081, p = 0.577). Postoperatively, there was significant reduction in all parameters (p < 0.001) and increase in LV (p < 0.003). The PAP regression was 39.42%; with the decrease in CTR, LA, and RA related to it, the early changes being significant (p < 0.01). The RV and PA showed lesser reduction (8.61% and 9.42%), late reduction being more conspicuous. The changes were greater and significant in Gp-II (especially PAP, RV, and PA). At 1 year, PAP normalized in only 19 (38%). Residual PH and chamber enlargement prevailed more in Gp-II.

CONCLUSIONS

This study emphasizes the importance of the baseline PAP in MS to which was proportionate the functional disability and the cardiac chamber alterations (except LA). Their postoperative improvement accompanying the PAP regression differed in degree and time frame relative to PAP. The higher pressure group showed greater regression, but greater prevalence of residual abnormalities, suggesting that the pathologic changes in them might take longer to resolve, necessitating further evaluation.

Persistent pulmonary artery hypertension in patients undergoing balloon mitral valvotomy

Pulmonary artery pressure (PAP) is known to regress after successful balloon mitral valvotomy (BMV). Data of persistent pulmonary artery hypertension (PPAH) following BMV is scarce. We analyzed the clinical, echocardiographic, and hemodynamic data of 701 consecutive patients who have undergone successful BMV in our institute from 1997 to 2003. Data of 287 patients who had PPAH (defined by pulmonary artery systolic pressure [PASP] of ≥ 40 mmHg at one year following BMV) were compared to the data of 414 patients who did not have PPAH. Patients who had PPAH were older (39.9 ± 9.9 years vs. 29.4 ± 10.1; P < 0.001). They had higher prevalence of atrial fibrillation (AF; 21.9 vs. 12.1%, P < 0.05), moderate or severe pulmonary artery hypertension (PAH) defined as PASP more than 50 mmHg (43.5 vs. 33.8%, P = 0.00), anatomically advanced mitral valve disease as assessed by Wilkin's echocardiographic score > 8 (33.7 vs. 23.2%, P < 0.001), and coexistent aortic valve disease (45.6 vs. 37.9%, P < 0.001) at the baseline. Those patients with PPAH had comparatively lower immediate postprocedural mitral valve area (MVA). On follow-up of more than five years, the occurrence of restenosis (39.3 vs. 10.1%, P = 0.000), new onset heart failure (14% vs. 4%, P < 0.05) and need for reinterventions (9.5% vs. 2.8%, P < 0.05) were higher in the PPAH group. Patients with PPAH were older, sicker, and had advanced rheumatic mitral valve disease. They had higher incidence of restenosis, new onset heart failure, and need for reinterventions on long term follow-up. PPAH represents an advanced stage of rheumatic valve disease and indicates chronicity of the disease, which may be the reason for the poorer prognosis of these patients. Patients with PPAH requires intense and more frequent follow-up.

Evaluation of pulmonary hypertension and surgical outcome by dynamic pulmonary perfusion imaging in patients with valvular disease

PURPOSE

The gold standard for assessing the degree of pulmonary hypertension is by right ventricular catheterization, an invasive procedure. This study was carried out to evaluate a noninvasive method using dynamic pulmonary perfusion imaging (DPPI) for assessing pulmonary hypertension and surgical outcome in patients with valvular heart disease.

METHODS

A total of 116 patients (50 men, 66 women, mean age: 45.8 ± 10.7 years) with valvular disease and 10 healthy volunteers (4 men, 6 women; mean age: 40.2 ± 12.8 years) were included in this study. Baseline DPPI with Tc-99m macroaggregated albumin and right ventricular catheterization were performed in all patients, before mitral valve replacement with or without aortic valve replacement surgery, and healthy volunteers. At 7 to 14 days postsurgery, 105 patients were re-evaluated with DPPI. A total lung region of interest was used to calculate a time-activity curve from the DPPI. The lung equilibrium time (LET: time from Tc-99m macroaggregated albumin entering the lungs to equilibrium) was measured. Receiver operating characteristic analysis of LET for diagnosing pulmonary hypertension was carried out.

RESULTS

LET in patients with valvular heart disease was significantly prolonged compared with those in 10 healthy volunteers (P < 0.001). LET was 14.79 ± 4.37 seconds and 27.78 ± 10.26 seconds in 10 healthy volunteers and patients, respectively). A strong correlation between LET and mean pulmonary arterial pressure (r = 0.827, P < 0.001) was found. Using mean pulmonary arterial pressure as a gold standard and threshold value of LET at 22.7 seconds, the sensitivity and specificity of LET for assessing pulmonary hypertension were found to be 94.7% and 78.0%, respectively. The pre- and postsurgery LET were found to be significantly different (27.48 ± 9.83 seconds vs. 21.33 ± 6.18 seconds, P < 0.001).

CONCLUSION

DPPI is an accurate and noninvasive method for evaluating pulmonary hypertension and surgical outcome in patients with valvular heart disease.

Hemodynamic impact of mitral prosthesis-patient mismatch on pulmonary hypertension: an in silico study

Recent clinical studies reported that prosthesis-patient mismatch (PPM) becomes clinically relevant when the effective orifice area (EOA) indexed by the body surface area (iEOA) is <1.2-1.25 cm(2)/m(2). To examine the effect of PPM on transmitral pressure gradient and left atrial (LA) and pulmonary arterial (PA) pressures and to validate the PPM cutoff values, we used a lumped model to compute instantaneous pressures, volumes, and flows into the left-sided heart and the pulmonary and systemic circulations. We simulated hemodynamic conditions at low cardiac output, at rest, and at three levels of exercise. The iEOA was varied from 0.44 to 1.67 cm(2)/m(2). We normalized the mean pressure gradient by the square of mean mitral flow indexed by the body surface area to determine at which cutoff values of iEOA the impact of PPM becomes hemodynamically significant. In vivo data were used to validate the numerical study, which shows that small values of iEOA (severe PPM) induce high PA pressure (residual PA hypertension) and contribute to its nonnormalization following a valve replacement, providing a justification for implementation of operative strategies to prevent PPM. Furthermore, we emphasize the major impact of pulmonary resistance and compliance on PA pressure. The model suggests also that the cutoff iEOA that should be used to define PPM at rest in the mitral position is approximately 1.16 cm(2)/m(2). At higher levels of exercise, the threshold for iEOA is rather close to 1.5 cm(2)/m(2). Severe PPM should be considered when iEOA is <0.94 cm(2)/m(2) at rest.