Immediate effects of percutaneous transvenous mitral commissurotomy on pulmonary hemodynamics at rest and during exercise in mitral stenosis

Long-Term Prognosis of Patients Who Underwent Percutaneous Transvenous Mitral Commissurotomy for Mitral Stenosis

The long-term prognosis for up to 20 years of patients who have undergone percutaneous transvenous mitral commissurotomy (PTMC) for mitral stenosis (MS) is unknown.We examined 77 of 93 patients (83%) with MS and who underwent PTMC from 1989 to 2002 at our institute, as well as the occurrence of either one of the following clinical endpoints until September 1, 2018: all-cause death or repeat intervention for the mitral valve.The mean follow-up duration was 20.5 ± 7.3 years. The mean age was 51 ± 11 years. Overall, the 20-year survival rate was 71% ± 5%; without any intervention, the 20-year survival rate was 40% ± 6%. In patients who achieved good immediate results (i.e., mitral valve area (MVA) of ≥ 1.5 cm² without mitral regurgitation (MR) of > 2/4 after PTMC), the 20-year survival rate was 80% ± 6%; without any intervention, the 20-year survival rate was 54% ± 7%.In our 20-year observational study, patients who have undergone PTMC for MS had favorable prognosis, especially in those who achieved good immediate results. In those who had poor immediate results, careful follow-up is needed because they might have more clinical event and any intervention for the mitral valve.

Shoulder Injuries in the Overhead Throwing Athlete

The overhead pitching motion is a coordinated sequence of movements that subjects the shoulder to extreme forces. The ultimate goal of this complex, dynamic activity is to generate high ball velocity and accuracy. In doing so, repetitive throwing can cause adaptive and pathologic changes in the thrower's shoulder. This article reviews the relevant shoulder anatomy, the kinetic chain, and throwing mechanics, as well as common shoulder injuries and surgical options for the treating orthopedic surgeon.

Advances in percutaneous treatment for adult valvular heart disease

Valvular heart disease occurs in 2-3% of the general population with an increase in prevalence with advancing age. The aetiology of valvular heart disease has evolved in recent decades with degenerative aortic and mitral valve disease supplanting rheumatic heart disease as a primary cause. The common valve lesions to be discussed in this article are aortic stenosis and mitral regurgitation. The traditional approach to calcific aortic stenosis when either symptoms or left ventricular impairment develops is surgical aortic valve replacement and it remains a treatment with excellent outcomes. In recent years there has been interest in less invasive approaches, including percutaneous and transapical aortic valve implantation. With refinements in technology these approaches are becoming a potential treatment option, primarily for high-risk patients who may otherwise be unsuitable for traditional open surgical treatment. Catheter-based approaches for mitral valve disease are also evolving. Mitral regurgitation may often be the result of mitral annular dilatation seen in patients with an enlarged left ventricle or left atrium. Percutaneous implantation of a constricting device in the coronary sinus, which lies in close proximity to the mitral annulus, results in a change to the geometry of the mitral valve and reduced regurgitation. Another technique in patients with degenerative mitral regurgitation is the endovascular edge-to-edge repair in which coaptation of the mitral valve leaflets can be improved with a percutaneously deployed clip. Small patient series indicate that these new techniques are promising. As such, advances in percutaneous interventional and surgical approaches have the potential to further improve outcomes for selected patients with valvular heart disease.

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

Balloon mitral valvotomy (BMV) provides improvement in pulmonary vascular resistance (PVR) in patients with severe mitral stenosis. Its normalization, however, remains questionable. We evaluated PVR before, after BMV, and at follow-up in 37 patients who had a previous successful BMV. Patients were divided into 2 groups: group 1 had 21 patients with normalized PVR (<125 dynes/s/cm5) either after BMV or at follow-up, and group 2 had 16 patients with persistently abnormal PVR. Patients in group 2 were older than patients in group 1 (55+/-13 vs 43+/-14 years, p = 0.01) and had atrial fibrillation more frequently (10 [63%] vs 6 [29%], p = 0.04). Age, cardiac rhythm, mitral valve area, pulmonary bed gradient, pulmonary artery pressure, and PVR before the procedure were significant univariate predictors for normalization of PVR. Age, echocardiographic score, systolic pulmonary artery pressure, and mitral regurgitation were all independent determinants of normalization of PVR in a multivariate logistic regression model. We conclude that PVR failed to return to normal in 16 patients (43%) after successful BMV; this can be predicted by baseline clinical and hemodynamic parameters.

Pulmonary vasoconstriction induced by mitral valve obstruction in sheep

We hypothesized that left atrial hypertension results in pulmonary vasoconstriction, which is obscured by the expected passive decrease in pulmonary vascular resistance. The objectives of this study were to demonstrate and quantify the vasoconstrictive changes that occur in the pulmonary circulation during experimental left atrial hypertension, to determine the site of vasoconstriction, and to explore its mechanism. Sheep were instrumented for measurement of pulmonary arterial (Ppa), left atrial (Pla), and systemic arterial pressures (Psa) with a Foley balloon catheter to variably obstruct the mitral valve. Distal pulmonary arterial wedge pressure (Ppaw) was determined by using a 5-Fr Swan-Ganz catheter that was advanced until it wedged with the balloon deflated. Cardiac output (CO) was estimated by thermodilution; pulmonary vascular resistances (PVR) were calculated as mean (Ppa - Pla)/CO = total PVR, (Ppa - Ppaw)/CO = upstream PVR, and (Ppaw - Pla)/CO = downstream PVR. We studied 15 awake sheep at baseline and during increases in Pla of 10 and 20 cmH2O, with and without inhalation of approximately 36 parts per million of nitric oxide. Left atrial hypertension resulted in elevation of Ppa. CO decreased only slightly at both levels of Pla elevation. Nitric oxide inhalation caused a significant decrease in PVR, which was greater as Pla increased. This vasodilator effect was most striking in downstream vessels. Experiments with phentolamine, atropine, and ibuprofen failed to reveal the mechanism of the reactive pulmonary vasoconstriction.

Factors determining the exercise capacity in mitral stenosis

In mitral stenosis, peak pulmonary pressure after exercise rather than valve area at rest or mitral gradient, was found to be an important factor in determining the exercise capacity.

Acute alterations of oxygen uptake and symptom-limited exercise time in patients with mitral stenosis after balloon valvuloplasty

STUDY OBJECTIVES

To determine the acute influence of improvement in orifice area in mitral stenosis by percutaneous transluminal valvuloplasty (PTVP) on cardiopulmonary exercise capacity, treadmill walking time (TWT), oxygen uptake parameters at maximum exercise as well as at highest comparable workloads and parameters of breathing work were assessed pre- and post-PTVP.

PATIENTS AND INTERVENTIONS

PTVP was carried out in 16 patients who had moderately severe mitral stenosis, bringing about an average increase in mitral valve orifice area from 1.0 +/- 0.1 cm2 to 2.2 +/- 0.5 cm2 (p < 0.0005). Based on standardized conditions, the patients (six in functional class A, five in class B, and five in class C according to Weber's classification) underwent symptom-limited treadmill cardiopulmonary exercise testing before as well as 2 days after PTVP. In addition, subgroup analysis (eight patients in sinus rhythm, eight patients in atrial fibrillation) was performed to determine a potential influence of the underlying cardiac rhythm on cardiopulmonary exercise parameters. To rule out a PTVP-independent training effect, a control group of ten patients with mitral stenosis underwent the same kind of cardiopulmonary exercise testing on 2 consecutive days.

MEASUREMENTS AND RESULTS

After-PTVP, TWT augmented by 19% (p < 0.0005) in all patients. Maximum oxygen uptake in percent of predicted maximal values at peak exercise and at anaerobic threshold was enhanced by 10% (p < 0.005). Ventilation at highest comparable workload was diminished by 10% (p < 0.025), whereas oxygen uptake and oxygen pulse at highest comparable workload did not differ, reflecting both unaltered cardiac output at comparable workloads and a more economic ventilation, respectively. Furthermore, PTVP-mediated alterations of TWT, but not of oxygen uptake at peak exercise were more pronounced in patients in sinus rhythm than in those in atrial fibrillation, reflecting more effective economization of cardiac work and ventilation in the former subgroup. Except for a statistically significant increase of TWT of 5%, no clinically relevant differences between both exercise tests were found with respect to oxygen uptake in the control group.

CONCLUSIONS

Impaired cardiopulmonary fitness in patients with moderately severe mitral stenosis is improved substantially by PTVP immediately after the intervention, mainly the result of acute reduction of pulmonary congestion and subsequent decrease in dead space to tidal volume ratio. Adherence to standardized conditions is considered crucial for comparability of cardiopulmonary data.