Prosthesis-Patient Mismatch in Individuals Undergoing Aortic Valve Replacement

Transcription

1 110 International Journal of Cardiovascular Sciences. 2016;29(2): ORIGINAL MANUSCRIPT Prosthesis-Patient Mismatch in Individuals Undergoing Aortic Valve Replacement Ramsés Miotto, Marcos Venicio Garcia Joaquim Instituto de Cardiologia de Santa Catarina São José, SC Brazil Abstract Background: Prosthesis-patient mismatch (PPM) in patients undergoing aortic valve replacement surgery is the subject of many research studies and is associated with worse prognosis in the long term. Objectives: To evaluate the incidence of PPM after aortic valve replacement surgery and characterize the clinical profile of patients undergoing this surgery. Methods: Cross-sectional observational retrospective study of 53 patients hospitalized for surgical treatment of severe aortic valve stenosis from January 2014 to June Three models of bioprosthesis and a metal prosthesis model were used. Indexed effective orifice area (ieoa) was calculated by dividing the effective orifice area provided by the prosthesis manufacturer by the body surface area of the recipient patient. The presence of PPM was defined when ieoa <0.90 cm²/m². Results: The average age of patients was 65,8±9,9. Male sex prevailed. Overall mortality rate was 11.3%. PPM occurred in 32.0% of patients, mostly of which were moderate degree. The prosthesis Biocor showed 70.5% of PPM while the Braile prosthesis showed no case. There was no difference in the reduction of transvalvular aortic gradients in the postoperative period between the groups with and without PPM. Conclusions: The patients profile is similar to that described in the literature, the incidence of PPM is high, varying greatly between the prosthesis models. There was no difference in the reduction of postoperative gradients between the groups with or without PPM. Keywords: Aortic valve stenosis; Heart valve prosthesis implantation; Prosthesis fitting; Prosthesis failure Introduction Aortic stenosis is the most common acquired valvular heart disease and its relevance, in terms of public health, rises progressively with population aging, considering that 2-4% of people older than 70 are affected by the disease. 1-5 The valve replacement surgery is the treatment of choice for aortic stenosis, considering the significant change of the natural evolution as clearly demonstrated by the studies of Schwarz et al. 6 and Pellikka et al. 7 Since the definition of prosthesis-patient mismatch (PPM) by Rahimtoola in 1978, this topic has been the subject of many research studies due to its influence on the prognosis of patients. 8 Prosthesis-patient mismatch is considered when the relationship between the effective orifice area of the valve prosthesis and the body surface area of the patient is reduced compared to the healthy native valve. Particularly, patients undergoing valve replacement surgery through aortic stenosis have a higher incidence of PPM compared to patients with aortic regurgitation, which can be explained by the degeneration and calcification of the aortic annulus and consequent narrowing present in aortic stenosis; aortic regurgitation is usually associated with the enlargement of the aortic annulus. Corresponding author: Ramsés Miotto Rua Adolfo Donato da Silva, s/n Praia Comprida São José, SC Brazil ramsesmiotto@gmail.com DOI: / Manuscript received on March 1, 2016; approved on April 12, 2016; revised on April 28, 2016.

2 Int J Cardiovasc Sci. 2016;29(2): ABBREVIATIONS AND ACRONYMS ECC endogenous creatinine clearance ICSC Instituto de Cardiologia de Santa Catarina IEOA indexed effective orifice area MTG mean transvalvular gradient PG peak gradient PPM prosthesis-patient mismatch PPM in classified into three levels of severity: mild, when the indexed effective orifice area is <0.90 cm²/m² and 0,85 cm²/m²; moderate, when <0.85 cm² and 0,65 cm²/m²; and severe, when <0.65 cm²/m² Prosthesis-patient mismatch is associated with less regression of symptoms and left ventricular hypertrophy, maintenance of elevated transvalvular gradients, decreased durability of prostheses and increased mortality in the long term. 10,12-16 The prostheses used and evaluated in this study were: the bioprosthesis Carpentier-Edwards Perimount model 2900 manufactured by Edwards Lifesciences (Irvine, California, USA); the bioprosthesis Biocor model B30 and the mechanical prosthesis model AJ-501 both manufactured by St Jude Medical (Saint Paul, Minnesota, USA) and the Braile bioprosthesis manufactured by Braile Biomédica (São José do Rio Preto, São Paulo, Brazil). The effective orifice area values taken from the manufacturers technical specifications obtained from in vitro tests conducted by the manufacturers (Chart 1) were used. Chart 1 Effective orifice area in cm² of valve prostheses This study aims to assess the incidence of PPM after aortic valve replacement surgery and characterize the clinical profile of patients undergoing this surgery. Size Prosthesis Carpentier (cm²) Methods Cross-sectional observational retrospective study of 53 patients hospitalized at Instituto de Cardiologia de Santa Catarina (ICSC) for surgical treatment of severe aortic valve stenosis from January 2014 to June This study has been approved by the Research Ethics Committee of the institution under no. CAAE Because this is a retrospective study, Informed Consent Form was not required. The institution s Statistical Services database was used to find all patients undergoing aortic valve replacement in the period cited and 93 individuals were identified. The study included patients older than 18, with severe stenosis of the native aortic valve who underwent aortic valve replacement (with or without coronary artery bypass grafting associated). Patients with other moderate or severe valve disease associated, with moderate or severe double valve lesion, patients with prosthetic valve and those undergoing valve re-replacement were excluded. At the end, there was a sample of 53 patients whose data were collected through the electronic medical records system Micromed and the database of the institution s Echocardiography Service. St Jude Biocor (cm²) NA NA St Jude Standard (cm²) NA Braile (cm²) NA = non-available For data collection, performed by one of the authors, a handwritten sheet establishing criteria and routine to evaluate the medical records was used. Echocardiography tests were performed during hospitalization for cardiologists specializing in echocardiography using the device Vivid E9 with the M5S transducer manufactured by GE (Waukesha, Wisconsin, USA). Ejection fraction was obtained by the biplane method; aortic valve area was obtained by the continuity equation method and the peak and mean gradients were obtained by continuous-wave left parasternal, apical or supraclavicular window Doppler. Body surface area was calculated by the Du Bois 17 formula and the indexed effective orifice area was obtained by dividing the effective orifice area of the prosthesis by the body surface area retrospectively from the anthropometric measurements stated on the patient records. Such measure did not influence the surgeons prosthesis choices.

3 112 Int J Cardiovasc Sci. 2016;29(2): For the endogenous creatinine clearance (ECC), we used the CKD-EPI 18 formula, which considers the serum creatinine, age, sex and ethnicity. Patients using antihypertensive medication were considered hypertensive; diabetics were considered to be those using oral hypoglycemic medication and/or insulin; dyslipidemia was considered when there was documentation through preoperative laboratory tests and/or use of lipid-lowering medication. The presence of coronary artery disease was determined in case of prior coronary event or previous coronary procedure or coronary angiography, demonstrating stenosis greater than 50%. To define chronic obstructive pulmonary disease, spirometry results were used when available and/or use of bronchodilators and inhaled corticosteroids. Peripheral occlusive vascular disease was defined when there was history of ischemic vascular event, bypass surgery, previous angioplasty or amputation. To estimate operative risk, EuroSCORE II was calculated retrospectively from patient records data through the electronic calculator available at For the electrocardiographic diagnosis of left ventricular hypertrophy, at least one of the following criteria was considered: Sokolow-Lyon, Sokolow-Lyon- Rappaport; Lewis; Cornell, Gubner-Ungerleider and Romhilt-Estes. 19,20 Data for categorical variables were described by absolute count and percentage and analyzed using Fisher s exact test or chi-square test. Data related to continuous variables were expressed as mean and standard deviation. Intra- and intergroup comparison of continuous variables was performed using paired and/or unpaired t-test; p<0.05 was considered significant. Data were analyzed using Microsoft Excel. Results The general characteristics of the group are shown in Table 1. The sample was predominantly male and mean age of 65.8±9.9 years. Most had clinical manifestations of dyspnea (NYHA functional class II and III) and angina pectoris. The predominant subtype of aortic stenosis in these patients was degenerative involvement with calcification. Table 1 General characteristics of the study sample (n=53) Variables Values Age in years (mean±sd) 65.8 ± 9.9 Male gender (%) 62.3 Comorbidities (%) Hypertension 56.6 Diabetes 30.2 Dyslipidemia 39.6 CAD 41.5 PVOD 5.7 COPD 11.3 ECC < 60 ml/min 26.4 Clinical conditions (%) Dyspnea 83.0 Chest pain 60.4 Syncope 14.0 LVH on ECG 82.0 Functional Class (NYHA) (%) Class I 9.6 Class II 30.8 Class III 44.2 Class ignored 15.4 Anthropometry (mean±sd) Body surface area (m²) 1.8 ± 0.2 Weight (kg) 71.0 ± 14.0 Height (cm) ± 32.1 Valve disease etiology (%) Three-valve calcified 75.4 Bicuspid valve 20.8 Rheumatic disease 3.8 EuroSCORE II rating (mean±sd) 2.1 ± 1.6 Isolated valve replacement (n, %) 38/ Valve replacement combined with MR (n,%) 15/ Minutes under CPB (mean±sd) 98.8 ± 40.9 Minutes in aortic clamping (mean±sd) 75 ± 28.9 CAD coronary artery disease; PVOD peripheral occlusive vascular disease; COPD chronic obstructive pulmonary disease; ECC endogenous creatinine clearance; LVH left ventricular hypertrophy; ECG electrocardiogram; NYHA New York Heart Association; CABG coronary artery bypass grafting; CPB cardiopulmonary bypass; SD standard deviation

4 Int J Cardiovasc Sci. 2016;29(2): On average, patients had left ventricular hypertrophy, preserved ejection fraction and high transvalvular gradients, as it can be seen on the preoperative echocardiography on Table 2. Table 2 Preoperative echocardiographic characteristics of the study sample Aortic valve area (cm²) 0.7 ± 0.2 Ejection fraction (%) 57.0 ± 18.9 IVS thickness (mm) 14.3 ± 2.7 LVPW thickness (mm) 13.5 ± 2.4 Peak transvalvular gradient (mmhg) 86.7 ± 26.0 Mean transvalvular gradient (mmhg) 56.1 ± 19.2 Values expressed as mean±standard deviation. IVS interventricular septum; LVPW left ventricular posterior wall Chart 1 specifies the effective orifice areas of the prosthesis according to the manufacturer and the nominal size, obtained from material published by the industry (values obtained by in vitro tests). Table 3 presents hospitalization time and hospital mortality data. The hospitalized patients studied waited 28.4±12.6 days on average to undergo surgery, amounting to an average hospital stay of 45.1±20.2 days. In-hospital mortality was 20.0% for those who underwent combined surgery and 7.9% for those who underwent isolated valve replacement. Table 3 Hospitalization of the study sample Pre-op hospitalization days (mean±sd) 28.4 ± 12.6 Hospitalization days in the ICU postoperatively (mean±sd) 8.1 ± 15.6 Post-op days in the ward (mean±sd) 16.7 ± 17.1 Total hospital stay (mean±sd) 45.1 ± 20.2 Overall hospital mortality (n,%) 6/ Hospital mortality in combined surgery (n,%) 3/ Hospital mortality in isolated valve replacement (n,%) 3/ Pre-op preoperative; Post-op post-operative; SD standard deviation Table 4 presents postoperative echocardiography data of the patients evaluated: none of them presented prosthesis dysfunction or severe paravalvular failure; there was mild paravalvular failure in 15.6% and moderate in 2.2% of patients. Peak and mean transvalvar aortic gradients were 31.5±11.3 mmhg and 17.2±7.5 mmhg, respectively. Table 4 Postoperative echocardiographic characteristics of the study sample Prosthesis dysfunction (%) 0.0 Mild paravalvular failure (%) 15.6 Moderate paravalvular failure (%) 2.2 Severe paravalvular failure (%) 0.0 Peak transvalvular gradient (mmhg) (mean±sd) Mean transvalvar gradient (mmhg) (mean±sd) 31.5 ± ± 7.5 There was no statistically significant difference in the reduction of the postoperative transvalvular gradient among the patients who did or did not present PPM (Table 5). A total of 17 (32.0%) patients presented PPM, of which 3 (5.6%) presented mild PPM, 13 (24.5%) presented moderate PPM and 1 (1.8%), severe PPM. Analyzing by prosthesis, 10 (18.8%) patients had Braile bioprosthesis implanted; 17 (32.0%) received the prosthesis St Jude Biocor, 8 (15.0%) received Carpentier and 18 (34.0%) patients received the metal prosthesis St. Jude Standard. All 53 patients had a statistically significant reduction in peak (PG) and mean (MG) transvalvular gradient compared to the preoperative value (Figure 1). No patient receiving the Braile prosthesis presented PPM. The following presented PPM: for the Biocor prosthesis 12 (70.5%) of the 17 patients; for the Carpentier prosthesis, 3 (37.5%) of the 8 patients; and 2 (11.1%) of the 18 patients who received the metal St. Jude Standard prosthesis. Between Biocor and Carpentier, there was no statistically significant difference in the incidence of PPM. There was a significant difference between Biocor and the metal St. Jude prosthesis (p=0.005) and between Biocor and Braille (p=0.0001).

5 114 Int J Cardiovasc Sci. 2016;29(2): Table 5 Comparison of reduction of gradients between the groups studied Patients with PPM (n=17) Patients without PPM (n=36) p value Pre-op peak grad 89.4 ± ± 26.7 ns Pre-op mean grad 57.6 ± ± 19.5 ns Post-op peak grad 34.3 ± ± 11.7 ns Post-op mean grad 17.1 ± ± 8.1 ns Pre- and post-operative mean peak gradients expressed in mmhg Grad gradient; Pre-op preoperative; Mean grad mean gradient; Post-op post-operative; ns non-significant; PPM prosthesis-patient mismatch Figure 1 Distribution of cases of PPM and pre- and postoperative gradients by prosthesis. PPM prosthesis-patient mismatch; PG peak gradient; MG mean gradient; Pre-op preoperative period; post-op postoperative period. Discussion The profile of the patients in this study is very similar to that found by other authors, 11,14,21-26 but the study sample showed higher percentage of patients with diabetes and chronic kidney disease. The larger number of patients with renal failure may be related to different definition criteria adopted: while in most studies the creatinine value was used, in this study, the endogenous creatinine clearance was used. All patients had a significant reduction of transvalvular gradients in relation to the preoperative period, however, there was no difference between patients with or without PPM. Mean postoperative PG values around 31.5±11.3 mmhg were found. Flameng et al. 14 found a significant difference in postoperative PG among patients with or without PPM, with mean values of 29.0±11.2 mmhg and 22.9±9.3 mmhg, respectively. The study of Hanayama et al. 25 found an average postoperative PG of 23.9±9.8 mmhg and an average MG of 13.6±6.5 mmhg, and showed a significant difference with a lower postoperative MG among patients without PPM. 25 These contradictory results, found in this study, are probably due to the small sample size and the absence

6 Int J Cardiovasc Sci. 2016;29(2): of data on the medical records for postoperative echocardiography. The general hospital mortality found in this study was 11.3%; however, for patients undergoing isolated aortic valve replacement, it was 7.9% lower than in another study conducted in Brazil in 2011, with patients undergoing isolated aortic valve replacement 21 and similar to the overall mortality of 7.2% obtained by Dayan et al. 22 Howell et al. 23 published a study in which they obtained mortality of 3.8% in a sample of 944 patients undergoing isolated aortic valve replacement, 23 which may be even lower according to other authors. 24,25,27 Several studies have shown that aortic valve replacement surgery associated with coronary artery bypass grafting increases mortality. In this study, 20% hospital mortality was found for combined surgery, which can be considered high, compared to the findings in the literature, ranging from 5.0 to 8.2%. 23,27,28 There is conflicting information about the best ieoa calculation methodology. Pibarot et al. 9 affirmed that the measurements from in vitro tests are similar to in vivo findings, suggesting that, for the evaluation of metal prostheses, in vitro measurements should be used, while others suggest that in vitro values are overestimated and which should be based on in vivo tests from echocardiography. 29,30 For the Braile prosthesis, no reference on in vivo hemodynamic performance was found, and in vitro data were used for all prostheses. Interestingly, none of the patients who received the Braile prosthesis presented PPM and the postoperative gradients tended to be smaller, but without statistical significance. Even considering that the EOA supplied by the manufacturers are overestimated, still, for the Biocor, the metal prosthesis St. Jude and Carpentier-Edwards Perimount 2900, there is a high prevalence of PPM, with worse performance found in the Biocor prosthesis. Similarly, this PPM proportion may be underestimated for the same reason. In this study, 32.0% patients with PPM were identified. Only one (1.88%) patient had severe PPM. Kaminishi et al. 24 obtained a total of 8.5% of patients with PPM, however, in their study, they used only mechanical prostheses, stentless models and Carpentier, known to have better hemodynamic profile. 24 Howell et al. 23 concluded that 8.6% of patients had severe PPM, which is much higher than our findings. Both authors used vitro data for the calculations. Other authors have used in vivo measurements to calculate the ieoa, including Blais et al. 11 who found 36.0% of moderate PPM and 2.0% severe PPM. Bleiziffer et al. 30 found 33.4% of moderate PPM and 6.3% of severe PPM. Flameng et al. 14 identified 46.0% of moderate PPM and 4.0% of severe PPM. Yap et al. 31 described 6.6% of severe PPM and Dayan et al. 22 reported 62.8% of moderate PPM and 1.8% of severe PPM. There is a difference in the incidence of PPM in studies with in vivo data compared to those with in vitro data for the definition of PPM, which reinforces the argument that in vitro test values are overestimated. Although the study sample is based on in vitro data, it was very similar to studies using in vivo data, which showed that the problem of PPM is very common, although severe cases are a minority. The problem of PPM is very common in the literature, as well as in the ICSC, where the prevalence is similar to that of major studies. This clinical situation has important prognostic implications and there should be efforts to minimize it, using surgeries to increase the aortic annulus and implant prostheses with a better hemodynamic profile. Some of the medical records searched included no data on the control echocardiography conducted before hospital discharge or during follow-up, which may have affected the calculation of postoperative gradients. However, this did not invalidate the research. The ieoa were calculated based on the technical specifications of the manufacturer of each prosthesis and no patient was submitted to control echocardiography to calculate ieoa using the continuity equation. In anyway, one should try to avoid the PPM by calculating the preoperative prosthesis size based on the specifications disclosed by the suppliers, although they can be obtained using non-standard methodologies and suffer commercial industry bias. 32 Conclusions The general characteristics of patients undergoing surgery are similar to those of other published studies. The incidence of PPM is high, but there are sharp

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