Jennifer Higgins

Effect of Prosthesis-Patient Mismatch on Long-Term Survival With Aortic Valve Replacement: Assessment to 15 Years

BACKGROUND The effect of prosthesis-patient mismatch on long-term survival after aortic valve replacement has received considerable attention but there remains controversy. This study was performed to determine the predictors of mortality after aortic valve replacement and influence of prosthesis-patient mismatch on survival. METHODS Contemporary mechanical prostheses and bioprostheses were implanted in 3,343 patients with aortic valve replacement between 1982 and 2003. The mean age was 68.06 +/- 11.20 years (median 70.06; range, 19 to 94), and the mean follow-up was 6.18 +/- 4.96 years, for a total of 20,666 years of follow-up. Prosthesis-patient mismatch was classified by effective orifice area index categories: normal (> 0.85 cm(2)/m(2)), 1,547 (46.3%); mild-to-moderate (> 0.65 cm(2)/m(2) to < or = 0.85 cm(2)/m(2)), 1,584 (47.4%); and severe (< 0.65 cm(2)/m(2)), 212 (6.3%). RESULTS The predictors of overall mortality were age, age categorization, New York Heart Association functional class III/IV, concomitant coronary artery bypass graft surgery, prosthesis type, preoperative congestive heart failure, diabetes mellitus, renal failure, and chronic obstructive pulmonary disease. All categories of effective orifice area indexes were not predictive of overall mortality, late mortality, or early mortality. The 15-year overall survival was differentiated by effective orifice area index categories: 38.1% +/- 2.1%, 37.0% +/- 2.2%, and 22.1% +/- 6.5%, respectively, for the three categories. Survival adjusted for the covariates (effective orifice area index, age, basal mass index, and ejection fraction) determined no effect except severe effective orifice area index when adjusted for ejection fraction more than 50% (p = 0.049). CONCLUSIONS Prosthesis-patient mismatch is not a predictor of overall standard unadjusted mortality to 15 years after aortic valve replacement, regardless of the category of effective orifice area index.

Early clinical outcomes after transapical aortic valve implantation: A propensity-matched comparison with conventional aortic valve replacement

OBJECTIVE Aortic valve replacement remains the standard treatment for symptomatic severe aortic stenosis. However, catheter-based approaches have recently emerged as therapeutic options for high-risk surgical candidates. The objective of this study is to use propensity scoring to compare early clinical outcomes after transapical aortic valve implantation and conventional aortic valve replacement. METHOD Propensity scoring based on logistic regression modeling of 16 preoperative patient characteristics was used to identify a group of very high-risk patients undergoing isolated conventional aortic valve replacement comparable to those patients undergoing transapical aortic valve implantation. McNemars test was used to compare early clinical outcomes between the 2 treatment groups, including 30-day mortality and in-hospital postoperative complications. RESULTS Ninety-two patients receiving transapical aortic valve implantation between October 2005 and April 2010 met inclusion criteria for this study. Half of these patients were successfully matched 1:1 to a patient receiving conventional aortic valve replacement. Baseline characteristics were similar between the 2 treatment groups after propensity matching. There were 4 perioperative deaths (8.7%) in the conventional aortic valve replacement group and 6 perioperative deaths (13%) in the transapical aortic valve implantation group (P > .05). There were no significant differences in the rates of cerebrovascular accidents, wound infections, reoperation for bleeding, or length of postoperative hospital stay between the 2 groups (P > .05). CONCLUSIONS Among high-risk propensity-matched patients, early clinical outcomes are similar after transapical aortic valve implantation and conventional aortic valve replacement. However, given the likelihood of residual selection bias, a prospective randomized trial is necessary to adequately compare the clinical outcomes after these 2 aortic valve procedures.

Influence of patient gender on mortality after aortic valve replacement for aortic stenosis

OBJECTIVE To assess the influence of gender on mortality after aortic valve replacement for aortic stenosis. METHODS A retrospective analysis was performed on data prospectively collected from all patients undergoing aortic valve replacement for aortic stenosis. Multivariate regression analysis was performed to evaluate the effect of 22 preoperative and operative variables on early, late, and overall mortality. RESULTS Aortic valve replacement was performed in 3343 patients with aortic stenosis between 1982 and 2003. The female patients were older, with a smaller body mass index. The women were less likely to have diabetes, chronic obstructive pulmonary disease, previous myocardial infarction, or left ventricular ejection fraction <35% but were more likely to have hypertension or a New York Heart Association III-IV classification. The female patients received a smaller prosthetic valve, with a smaller effective orifice area index (EOAI). The mean follow-up period was 6.18 ± 4.96 years, with a total of 2066.142 years of follow-up. The independent predictors of early mortality for the male patients included age, concomitant surgical revascularization, congestive heart failure, and valve size of ≤21 mm. The independent predictors of late mortality for the male patients included age, concomitant surgical revascularization, diabetes, renal failure, chronic obstructive pulmonary disease, congestive heart failure, and a bioprosthetic valve. The independent predictors of overall mortality for the male patients included age, concomitant surgical revascularization, diabetes, renal failure, heart failure, and valve size of ≤21 mm. For the female patients, the risk factors for early mortality included body mass index <25 kg/m(2); for late mortality included age, concomitant surgical revascularization, New York Heart Association class III-IV, and diabetes; and for overall mortality included age, concomitant surgical revascularization, New York Heart Association class III-IV, and renal failure. Furthermore, male gender was an independent predictor of late (but not early or overall) mortality. CONCLUSIONS The independent predictors of mortality after aortic valve replacement for aortic stenosis differed between the male and female patients. Male gender increased the risk of late mortality, and a valve size of ≤21 mm increased the risk of early and overall mortality among the male patients only. These differences need to be taken into consideration preoperatively and require consideration during operative management.

Microaxial Devices for Ventricular Failure: A Multicentre, Population-Based Experience

BACKGROUND Impella microaxial devices provide circulatory assistance for patients with acute decompensated heart failure. This study reviews the population-based provincial experience in British Columbia. METHODS We performed a retrospective review of the prospectively maintained database. Impella devices were inserted for acute cardiogenic shock refractory to maximal therapy, as a bridge to decision or to long-term mechanical support. RESULTS Between August 2007 and September 2009, 35 patients received 37 Impella devices (Impella LP 2,5, n=2; Impella LP 5,0, n=29; and Impella RD 5.0, n=6) (Abiomed Inc, Danvers, MA). Devices were inserted in the setting of dilated cardiomyopathy (n=13), acute myocardial infarction (n=6), postcardiotomy shock (n=6), and other etiologies (n=12). Mean age was 53.0±13.7 years. Mean left ventricular ejection fraction was 19±9% at the time of insertion. Nineteen patients required aggressive resuscitation, all patients were on inotropic support, 97% of patients were intubated, and 46% of patients received mechanical circulatory support prior to insertion of the Impella devices. Mean duration of support was 3.7±3.0 days. In all, 49% were successfully weaned, and 22% were transferred to long-term mechanical support. Four patients have subsequently undergone successful cardiac transplantation. The 30-day mortality was 40%, and 6-month mortality was 49%. Complications included gastrointestinal bleeding (n=1), hemoptysis (n=1), and thrombocytopenia (n=4). There were no cardiovascular or cerebrovascular events. CONCLUSION Temporary support with Impella microaxial ventricular assist devices adds a valuable therapeutic option in selected patients with acute decompensated heart failure.

Cardiac computed tomography facilitates operative planning in patients with mitral calcification.

Extensive mitral annular calcification (MAC) can represent a significant surgical challenge. We use three illustrative examples to describe our early experience with electrocardiogram-gated cardiac computed tomography (CT) as a preoperative tool to localize MAC and to predict requisite surgical techniques. In all three cases, cardiac CT accurately delineated the location and extent of calcification compared with intraoperative findings, and in each case, it assisted in predicting the required operation (avoidance vs resection of calcification; need for annular reconstruction). All 3 patients experienced an uneventful postoperative course with no evidence of paravalvular leak on follow-up echocardiography.

Influence of Prosthesis-Patient Mismatch on Survival with Aortic Valve Replacement

Prosthesis-patient mismatch (PPM) was first described over 30 years ago (Rahimtoola, 1978) for aortic valve replacement: when the in vivo effective orifice area (EOA) of the prosthetic valve is less than that of the native, non-diseased, human valve. Extensive documentation on the role of PPM after aortic valve replacement (AVR) particularly addresses left ventricular mass regression and patient survival. Controversy continues about the influence of PPM on patient survival, both early and late mortality. Many studies (Pibarot and Dumesnil, 2000; Muneretto et al., 2004; Mohty et al., 2006; Tasca et al., 2006; Moon et al., 2006; Florath et al., 2008; Mohty et al., 2009; Blais et al., 2003) report PPM to be an independent predictor of mortality while others (Jamieson et al., 2010; Kato et al., 2007; Vicchio et al., 2008; Mascherbauer et al., 2008; Monin et al., 2007) showed no significant effect of PPM on patient outcome. There is also debate about whether the control of PPM reduces congestive heart failure and regression of the left ventricular mass, thereby contributing to improved survival. Several Canadian centers have been actively involved in this area of research, namely the Laval University group led by P. Pibarot, J.G. Dumesnil and D. Mohty, the UBC group led by W.R.E. Jamieson, and the University of Ottawa group led by M. Ruel and A. Kulik. PPM is categorized by Pibarot and Dumesnil (2000), Mohty et al. (2009), and Jamieson et al. (2010) as normal (EOA index (EOAI) of > 0.85 cm2 / m2), mild-to-moderate (> 0.65 cm2 / m2 to ≤ 0.85 cm2 / m2), and severe (≤ 0.65 cm2 / m2). Tasca et al. (2006) defined PPM as an EOAI of ≤ 0.80 cm2 / m2, Moon et al. (2006) as an EOAI of < 0.75 cm2 / m2, while Ruel et al. (2004), Kulik et al. (2006), Kato et al. (2007), and Monin et al. (2007) as EOAI of ≤ 0.85 cm2 / m2; Florath et al. (2008) and Vicchio et al. (2008) chose 0.60 cm2 / m2 as the cutoff between moderate and severe PPM. As can be seen, there is no clear consensus on the exact definition of PPM; this lack of consensus may contribute at least in part to the observed discrepancies in the conclusions of the studies. The studies also differ in the length of their patient followup. Jamieson et al. (2010) report survival to 15 years, Moon et al. (2006) and Mohty et al. (2009) to 12 years, and the majority of the other publications on the topic of PPM report survival from 4 to 8 years (Mothy et al. 2006; Tasca et al., 2006; Florath et al., 2008; Kato et al., 2007; Mascherbauer et al., 2008; Monin et al., 2007). These differences may also contribute to the different conclusions reached.