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PPM - prosthesis‐patient mismatch

The definition and incidence of patient-prosthesis mismatch (PPM) in the mitral position are unclear.

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Patient-Prosthesis Mismatch After Mitral Valve …

We hypothesized that EOA derived from in vivo postoperative measure using CE would be most valid compared with other parameters including PHT method and reference EOA for the evaluation of mitral PPM. Therefore, we investigated the incidence of PPM in the mitral position using different methods of EOA determination, including calculation by CE, calculation by PHT and use of reference EOA, and compared them with various echocardiographic variables in patients with mitral stenosis after MVR.

Evaluation of Patient-Prosthesis Mismatch

The results of the study were based on retrospective analysis; however, we carefully reviewed patient medical records and echocardiography. As our findings are based upon an observational cohort of patients with rheumatic mitral stenosis, they may not necessarily be generalizable to all patients with mitral regurgitation. We compared indexed EOA to systolic PA pressure, not clinical outcome, since the studied group was at relatively low risk for cardiovascular events, as indicated by the low prevalence of combined co-morbidities such as hypertension and diabetes. In addition, functional data, such as maximum exercise capacity and maximum oxygen consumption, which would be more helpful for identifying the clinical implication of mitral PPM, were not included. Prevalence of pulmonary hypertension (systolic PA pressure >40 mm Hg) was relatively low, and therefore, further investigation into the clinical significance of the results of the current study is needed. Patients with atrial fibrillation were included in the study population, although five cardiac cycles were recorded and these results were averaged. We used linear regression analysis to determine independent predictors of systolic PA pressure, although we cannot conclude that there is no association just because the linear regression is not significant. Nevertheless, the association with EOAIPHT and EOAIR is unlikely, since there were no significant differences in systolic PA pressure between the groups, and the multivariate regression analysis showed that EOAIPHT and EOAIR were not predictors of systolic PA pressure.

PROSTHESIS-PATIENT MISMATCH IN VALVULAR …

prosthesis-patient mismatch in valvular heart disease: an evaluation of echocardiographic findings

Patient-prosthesis mismatch (PPM) in the aortic position has been studied for a decade and is a widely accepted concept, although its exact influence on long-term outcome remains controversial (). Despite the fact that the cardiac output is the same through the aortic and the mitral valve, the adequacy between a patient’s surface area and the valve’s area has been less studied in the mitral position. The consequence of Poiseuille’s law related to the given cardiac output that flows through a restrictive mitral valve is more obscure in the mitral position. Thus, the clinical impacts might be more difficult to identify and the threshold ratio between the effective orifice area (EOA) of the valve and the body surface area (BSA) defined as the indexed EOA (EOAi) remains to be defined. A strong correlation was identified between the persistence of residual pulmonary hypertension after mitral valve replacement and an EOAi of lower than 1.2 cm2/m2 (). The same threshold was associated with recurrent heart failure and worse long-term survival (,). Some studies on this subject have included bioprosthetic valves that are subject to deterioration, especially in the mitral position, with a theoretical orifice area that could be overestimated compared with the actual one, especially a few years after implantation. The main objective of the present study was to evaluate the incidence of mitral PPM in a large population of patients with mechanical mitral valve replacement and its effect on long-term outcome.

In the aortic position, PPM is defined using the ratio of EOA to BSA because it best represents the geometric properties of a prosthetic valve. An absolute threshold value between the presence of mismatch and no mismatch probably does not exist, but an inflection point in the curve relating the EOA/BSA ratio to mismatch is chosen to help the decision-making process in valve implantation. In the aortic position, an EOA/BSA ratio of lower than 0.85 cm2/m2 has been associated with worse outcome (). In the mitral position, only a few studies have been conducted. Lam et al () reported a negative impact on survival when the EOA/BSA ratio was lower than 1.22 cm2/m2. In the present study, we used three thresholds (1.2 cm2/m2, 1.3 cm2/m2 and 1.4 cm2/m2) and found the same negative impact on long-term survival at the 1.3 cm2/m2 threshold, with 10.1% of the patients presenting such a mismatch. This compares well with the report by Lam et al of 13.8% of the patients with a ratio lower than 1.22 cm2/m2. The small difference could be related to the choice of EOA values for different prostheses, which are still subject to debate.

Prosthesis-patient mismatch after ..

Prosthesis-Patient Mismatch in Bovine Pericardial …

There may be several explanations concerning the conflicting data on the clinical effect of PPM after MVR. First, different valve types and patients groups were employed in the studies. Especially, patients suffering PPM have sometimes additional risk factors, including hypertension and diabetes, which could also affect long-term survival. Second, when evaluating the impact of PPM after MVR, it is also important to consider pathophysiological status of patients. In the current study, minimize those problems, we included only patients with rheumatic mitral stenosis and analyzed postoperative echocardiography 12 to 60 months after MVR, thus avoiding dynamic changes of hemodynamic status at early postoperative period and the late development of prosthetic valve malfunction which might be associated with pannus formation. Consequently, we found that PPM determined by CE showed significant correlation with various postoperative hemodynamic parameters.

In view of the above, the following points need to be emphasised. Firstly, it is not the size (labelled size or IGA) of the prosthesis that matters but rather its EOA and in whom you implant it. Secondly, the only parameter yet shown to be valid to define PPM is the indexed EOA. Thirdly, the indexed IGA and labelled valve size cannot be used to identify PPM or to characterise its severity. To avoid any confusion about the interpretation of results of the different studies, the terminology used to describe these phenomena also apparently must be consistent and without ambiguity. Hence, “indexed orifice area” should not be used without specifying whether it is the indexed IGA or the indexed EOA. Also, given that the term PPM stems from a haemodynamic concept, its use should be reserved for data relating to haemodynamic function (that is, indexed EOAs and gradients), whereas the results of studies based on the analysis of the IGA or labelled valve size would be more appropriately described in terms of patient‐prosthesis size but without using the term mismatch, thus avoiding much confusion. The use of adequate terminology has important clinical implications, since, as mentioned, patient‐prosthesis size has little relevance to adverse clinical outcomes, whereas PPM can be viewed as a major risk factor in this regard.,,,,,,,,,,,,

Hemodynamic Evaluation; Prosthesis–Patient Mismatch; ..
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    Patient-prosthesis mismatch after transapical aortic valve implantation

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  • Patient-prosthesis mismatch in the mitral position …

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Prosthesis-patient mismatch in aortic stenosis | …

Prosthesis‐patient mismatch (PPM) is present when the effective orifice area of the inserted prosthetic valve is too small in relation to body size. Its main haemodynamic consequence is to generate higher than expected gradients through normally functioning prosthetic valves. This review updates the present knowledge about the impact of PPM on clinical outcomes. PPM is common (20–70% of aortic valve replacements) and has been shown to be associated with worse haemodynamic function, less regression of left ventricular hypertrophy, more cardiac events, and lower survival. Moreover, as opposed to most other risk factors, PPM can largely be prevented by using a prospective strategy at the time of operation.

Effect of the prosthesis–patient mismatch on long-term clinical ..

The incidence of prosthesis-patient mismatch (PPM) after mitral valve replacement (MVR) has been reported to vary. The purpose of the current study was to investigate incidence of PPM according to the different methods of calculating effective orifice area (EOA), including the continuity equation (CE), pressure half time (PHT) method and use of reference EOA, and to compare these with various echocardiographic variables.

Patient–prosthesis mismatch after mitral valve …

Prosthesis-patient mismatch (PPM) can be considered after insertion into the patient when the effective orifice area (EOA) is of the prosthesis valve and is less than that of a normal human valve, which results in an increased postoperative transvalvular gradient.,

Prosthesis-Patient Mismatch after Mitral Valve …

The alternative options to avoid PPM (options 1 and 2) should of course be considered in light of the patient's clinical condition and overall risk to benefit ratio. If, for example, the projected indexed EOA is 0.75–0.80 cm2/m2 in a patient who is sedentary and has good LV function and it is evaluated that option 1 or 2 would significantly increase the operative risk, accepting this level of PPM may be the best option for this particular patient. If, on the other hand, severe PPM is projected or if the patient has poor LV function, the risks associated with PPM would be much higher and would probably outweigh any additional risks considered to be associated with options 1 and 2. Whatever the option chosen, we advocate performing this simple exercise in all cases, since it allows an enlightened clinical decision about the overall risks confronting the patient.

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