Implications of increased left ventricular mass index on in-hospital outcomes in patients undergoing aortic valve surgery

Left ventricular hypertrophy as a predictor of cardiovascular outcomes after transcatheter aortic valve replacement

AIMS

This study aimed to clarify the relationship between cardiovascular prognosis and left ventricular hypertrophy (LVH) in patients with severe aortic stenosis who underwent transcatheter aortic valve replacement (TAVR) and to investigate the relationship between cardiac sympathetic nerve (CSN) function and these factors using ¹²³ I-metaiodobenzylguanidine scintigraphy.

METHODS AND RESULTS

In this single-centre, retrospective observational study, 349 patients who underwent TAVR at our institution between July 2017 and May 2020 were divided into two groups: those with severe LVH pre-operatively [severe LVH (+) group] and those without LVH pre-operatively [severe LVH (-) group]. The rates of freedom from cardiovascular events (cardiovascular death and heart failure hospitalization) were compared. The relationship between changes in left ventricular mass index (LVMi) and changes in delay heart-mediastinum ratio (H/M) from before TAVR to 6 months after TAVR was also investigated. The event-free rate was significantly lower in the severe LVH (+) group (87.1% vs. 96.0%, log-rank P = 0.021). The severe LVH (+) group exhibited a significantly lower delay H/M value, scored by ¹²³ I-metaiodobenzylguanidine scintigraphy, than the severe LVH (-) group (2.33 [1.92-2.67] vs. 2.67 [2.17-3.68], respectively, P < 0.001). Moreover, the event-free rate of post-operative cardiovascular events was lower among patients with a delay H/M value < 2.50 than that among other patients (87.7% vs. 97.2%, log-rank P = 0.012). LVMi was significantly higher (115 [99-130] vs. 90 [78-111] g/m² , P < 0.001) and delay H/M value was significantly lower (2.53 [1.98-2.83] vs. 2.71 [2.25-3.19], P = 0.025) in the severe LVH (+) group than in the severe LVH (-) group at 6 months after TAVR. Patients with improved LVH at 6 months after TAVR also had increased delay H/M (from 2.51 [2.01-2.81] to 2.67 [2.26-3.02], P < 0.001), whereas those without improved LVH had no significant change in delay H/M (from 2.64 [2.23-3.06] to 2.53 [1.97-3.00], P = 0.829).

CONCLUSIONS

Severe LVH before TAVR is a prognostic factor for poor post-operative cardiovascular outcomes. LVH associated with aortic stenosis and CSN function are correlated, suggesting their involvement in LVH prognosis.

Extent of Left Ventricular Mass Regression and Impact of Global Left Ventricular Afterload on Cardiac Events and Mortality after Aortic Valve Replacement

Patient-prosthesis mismatch (PPM) causes a high transvalvular pressure gradient and residual left ventricular (LV) hypertrophy, consequently influencing long-term results. This study aimed to find the relationships between hemodynamic parameters and LV mass regression and determine the risk predictors of major adverse cardiovascular and cerebral events (MACCE) after aortic valve replacement (AVR) for aortic stenosis. Methods and Results: Preoperative and postoperative Doppler echocardiography data were evaluated for 120 patients after AVR. The patients' mean age was 67.7 years; 55% of the patients were male. Forty-four (37%) patients suffered from MACCE during a mean follow-up period of 3.6 ± 2 years. The following hemodynamic parameters at follow-up were associated with lower relative indexed LV mass (LVMI) regression: lower postoperative indexed effective orifice area, greater mean transvalvular pressure gradient (MPG), greater stroke work loss (SWL), and concentric or eccentric LV remodeling mode. The following hemodynamic parameters at follow-up were associated with a higher risk of MACCE: higher valvuloarterial impedance (Z_VA), greater SWL, greater MPG, greater relative wall thickness, greater LVMI, and hypertrophic LV remodeling mode. Lower relative LVMI regression was associated with a higher risk of MACCE (hazard ratio, 1.01: 95% confidence interval, 1.003-1.03). The corresponding cutoff of relative LVMI regression was -14%. Conclusions: Changes in hemodynamic parameters were independently associated with relative LVMI regression. Impaired reverse remodeling and persistent residual LV hypertrophy were independent risk predictors of MACCE. An LVMI regression lower than 14% indicated higher MACCE. A postoperative Z_VA greater than 3.5 mmHg/mL/m² was an independent risk predictor of cardiac events and mortality after AVR. Preventive strategies should be used at the time of the operation to avoid PPM.

The cardiac computed tomography-derived extracellular volume fraction predicts patient outcomes and left ventricular mass reductions after transcatheter aortic valve implantation for aortic stenosis

BACKGROUND

Transcatheter aortic valve implantation (TAVI) improved outcome of patients with severe aortic valve stenosis (AS). Myocardial fibrosis is associated with AS-related pathological left ventricular (LV) remodeling and predicts cardiovascular mortality after TAVI. The present study aimed to investigate the impact of preoperative extracellular volume (ECV) assessed by computed tomography (CT) on left ventricular mass (LVM) regression and clinical outcomes in severe AS patients after TAVI.

METHODS

We examined 71 consecutive severe AS patients who underwent CT with ECV determination before TAVI. ECV was calculated as the ratio of the change in Hounsfield units in the myocardium and LV blood before and after contrast administration, multiplied by (1-hematocrit). Delayed scan was performed at 5 min after contrast injection. Echocardiography was performed before and 6 months after TAVI. The primary endpoint was heart failure (HF) hospitalization after TAVI. Patients were divided into two subgroups according to the median value of global ECV with 32 % (Low-ECV group: n = 35, and High-ECV group: n = 36).

RESULTS

No significant differences were observed in background characteristics between the 2 groups. However, the preoperative LV ejection fraction and LVM index were similar between the 2 groups, the Low-ECV group had greater LVM index reduction than the High-CV group after 6 months (p < 0.001). Kaplan-Meier curves demonstrated that the High-ECV group had significantly higher rate of HF hospitalization than the Low-ECV group (p = 0.016). In addition, multivariate analyses identified high global ECV as an independent predictor of HF hospitalization (HR 10.8, 95 % confidence interval 1.36 to 84.8, p = 0.024).

CONCLUSION

The low preoperative ECV assessed by CT is associated with the greater LVM regression, and predict better outcome in AS patients after TAVI.

Left Ventricular Hypertrophy and Biomarkers of Cardiac Damage and Stress in Aortic Stenosis

Background

Left ventricular hypertrophy (LVH) is associated with increased mortality risk and rehospitalization after transcatheter aortic valve replacement among those with severe aortic stenosis. Whether cardiac troponin (cTnT) and NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) risk stratify patients with aortic stenosis and without LVH is unknown.

Methods and Results

In a multicenter prospective registry of 923 patients with severe aortic stenosis undergoing transcatheter aortic valve replacement, we included 674 with core‐laboratory‐measured LV mass index, cTnT, and NT‐proBNP. LVH was defined by sex‐specific guideline cut‐offs and elevated biomarker levels were based on age and sex cut‐offs. Adjusted Cox proportional hazards models evaluated associations between LVH and biomarkers and all‐cause death out to 5 years. Elevated cTnT and NT‐proBNP were present in 82% and 86% of patients with moderate/severe LVH, respectively, as compared with 66% and 69% of patients with no/mild LVH, respectively (P<0.001 for each). After adjustment, compared with no/mild LVH, moderate/severe LVH was associated with an increased hazard of mortality (adjusted hazard ratio [aHR], 1.34; 95% CI 1.01–1.77, P=0.043). cTnT and NT‐proBNP each risk stratified patients with moderate/severe LVH (P<0.05). In a model with both biomarkers and LVH included, elevated cTnT (aHR, 2.08; 95% CI 1.45–3.00, P<0.001) and elevated NT‐proBNP (aHR, 1.46; 95% CI 1.00–2.11, P=0.049) were each associated with increased mortality risk, whereas moderate/severe LVH was not (P=0.15).

Conclusions

Elevations in circulating cTnT and NT‐proBNP are more common as LVH becomes more pronounced but are also observed in those with no/minimal LVH. As measures of maladaptive remodeling and cardiac injury, cTnT and NT‐proBNP predict post‐transcatheter aortic valve replacement mortality better than LV mass index. These findings may have important implications for risk stratification and treatment of patients with aortic stenosis.

Segmentally impaired left ventricular longitudinal strain: a new predictive diagnostic parameter for asymptomatic patients with severe aortic stenosis and preserved ejection fraction

INTRODUCTION

This study aims to investigate the correlation between severe aortic stenosis (sAS) and impairment of left ventricular global longitudinal strain (LVGLS) in particular segments, using two-dimensional speckle tracking echocardiography in patients with sAS and normal ejection fraction of left ventricle (LVEF).

METHODS

The study included 53 consecutive patients with asymptomatic sAS and preserved LVEF. The regional longitudinal systolic LV wall strain was evaluated at the area opposite of the aorta as the median strain value of the basal, middle, and apical segments of the lateral and posterior walls and was compared to the average strain value of the interventricular septum (IVS) at the same views.

RESULTS

LVGLS was decreased and was not statistically different between three- and four-chamber views (-12.5 ± 3.6 vs -11.4 ± 5.5%, p = 0.2). The average strain values of the lateral and posterior walls were statistically reduced compared to the average value of the IVS (lateral vs IVS: -7.8 ± 3.7 vs -10 ± 5.3%, p = 0.005, posterior vs IVS: -7.7 ± 4.2 vs -10.3 ± 3.8%, p < 0.0001). There was no significant difference between lateral and posterior walls (-7.8 ± 3.7 vs -7.7 ± 4.2%, p = 0.9).

CONCLUSIONS

The strain of lateral and posterior walls of left ventricle, which lay just opposite to the aortic valve seem to be more reduced compared to other walls in patients with sAS and preserved LVEF possibly due to their anatomical position. This impairment seems to be the reason of the overall LVGLS reduction. Regional strain could be used as an extra tool for the estimation of the severity of AS as well as for prognostic information in asymptomatic patients.

Osteopontin as novel biomarker for reversibility of pressure overload induced left ventricular hypertrophy

Aim: The aim of this study was to evaluate the prognostic value of osteopontin (OPN) as a marker for left ventricular (LV) hypertrophy and its reversibility after surgical aortic valve replacement (SAVR). Patients & methods: Echocardiographic data and OPN plasma levels of 149 consecutive patients undergoing SAVR were obtained preoperatively and 3 months postoperatively. OPN was measured by Quantikine Human OPN immunoassay. Results: There was a significant correlation between higher OPN plasma levels and lower LV-mass regression. In patients receiving SAVR combined with coronary artery bypass grafting, high OPN plasma levels were also an indicator for eccentric hypertrophy phenotype. Conclusion: OPN may be a useful indicator for LV hypertrophy phenotype and could have a prognostic value to estimate LV-mass regression after SAVR.

Association between Serum Mg2+ Concentrations and Cardiovascular Organ Damage in a Cohort of Adult Subjects

Magnesium (Mg²⁺) levels are associated with insulin resistance, hypertension, atherosclerosis, and type 2 diabetes (T2DM). We evaluated the clinical utility of physiological Mg²⁺ in assessing subclinical cardiovascular organ damage including increased carotid artery intima- media thickness (c-IMT) and left ventricular mass index (LVMI) in a cohort of well-characterized adult non-diabetic individuals. Age- and gender-adjusted correlations between Mg²⁺ and metabolic parameters showed that Mg²⁺ circulating levels were correlated negatively with body mass index (BMI), fasting glucose, and 2h-oral glucose tolerance test (OGTT) glucose. Similarly, Mg²⁺ levels were significantly and negatively related to c-IMT and LVMI. A multivariate regression analysis revealed that age (β = 0.440; p < 0.0001), BMI (β = 0.225; p < 0.0001), and Mg²⁺ concentration (β = −0.122; p < 0.01) were independently associated with c-IMT. Age (β = 0.244; p = 0.012), Mg²⁺ (β = −0.177; p = 0.019), and diastolic blood pressure (β = 0.184; p = 0.038) were significantly associated with LVMI in women, while age (β = 0.211; p = 0.019), Mg²⁺ (β = −0.171; p = 0.038) and the homeostasis model assessment index of insulin resistance (HOMA-IR) (β = −0.211; p = 0.041) were the sole variables associated with LVMI in men. In conclusion, our data support the hypothesis that the assessment of Mg²⁺ as part of the initial work-up might help unravel the presence of subclinical organ damage in subjects at increased risk of cardiovascular complications.

Left Ventricular Hypertrophy Does Not Affect 1-Year Clinical Outcomes in Patients Undergoing Transcatheter Aortic Valve Replacement

OBJECTIVES

The aim of this study was to evaluate the association between pre-procedural left ventricular hypertrophy (LVH) patterns and clinical outcomes after transcatheter aortic valve replacement (TAVR).

BACKGROUND

The association between pre-procedural LVH pattern and severity and clinical outcomes after TAVR is uncertain.

METHODS

Patients (n = 31,199) across 422 sites who underwent TAVR from November 2011 through June 2016 as part of the Society of Thoracic Surgeons/American College of Cardiology TVT (Transcatheter Valve Therapies) Registry linked with the Centers for Medicare and Medicaid Services database were evaluated by varying LVH patterns, according to sex-specific cutoffs for left ventricular mass index and relative wall thickness. The association between LVH pattern (concentric remodeling, concentric LVH, and eccentric LVH) and outcomes (rates of mortality, myocardial infarction [MI], stroke, new dialysis requirement) at 1-year follow-up were evaluated using multivariate hazard models.

RESULTS

There were no significant associations between concentric remodeling (death: adjusted hazard ratio [HR]: 1.03; 95% confidence interval [CI]: 0.93 to 1.15; MI: HR: 1.05; 95% CI: 0.76 to 1.46; stroke: HR: 1.11; 95% CI: 0.89 to 1.39; new dialysis: HR: 0.86; 95% CI: 0.64 to 1.15), concentric LVH (death: HR: 1.04; 95% CI: 0.95 to 1.15; MI: HR: 1.12; 95% CI: 0.82 to 1.52; stroke: HR: 1.14; 95% CI: 0.92 to 1.40; new dialysis: HR: 1.17; 95% CI: 0.90 to 1.52), or eccentric LVH (death: HR: 0.98; 95% CI: 0.87 to 1.10; MI: HR: 1.07; 95% CI: 0.71 to 1.63; stroke: HR: 1.01; 95% CI: 0.78 to 1.32; new dialysis: HR: 1.25; 95% CI: 0.92 to 1.70) and outcomes at 1 year compared with patients without LVH.

CONCLUSIONS

In a contemporary cohort of patients who underwent TAVR, pre-procedural LVH according to left ventricular mass index and relative wall thickness was not associated with adverse outcomes at 1-year follow-up. TAVR is likely to benefit patients with severe aortic stenosis regardless of the presence of LVH.

Impact of preprocedural left ventricle hypertrophy and geometrical patterns on mortality following TAVR

BACKGROUND

In contrast to surgical aortic valve replacement, left ventricle (LV) hypertrophy (LVH) had not been clearly associated with mortality following transcatheter aortic valve replacement (TAVR).

METHODS

We performed a retrospective analysis of patients enrolled in the Israeli multicenter TAVR registry for whom preprocedural LV mass index (LVMI) data were available. Patients were divided into categories according to LVMI: normal LVMI and mild, moderate, and severe LVH. Mild LVH was regarded as the reference group. Additionally, LV geometry patterns were examined (concentric and eccentric LVH, and concentric remodeling).

RESULTS

The cohort consisted of 1,559 patients, 46.5% male, with a mean age of 82.2 (±6.8) years and mean LVMI of 121 (±29) g/m². Rates of normal LVMI and mild, moderate, and severe LVH were 31% (n = 485), 21% (n = 322), 18% (n = 279), and 30% (n = 475), respectively. Three-year mortality rates for normal LVMI and mild, moderate, and severe LVH were 19.8%, 18.3%, 23.7%, and 24.4%, respectively. Compared to mild LVH, moderate LVH and severe LVH were independently associated with an increased risk for all-cause mortality (hazard ratio [HR] 1.58, 95% CI 1.15-2.18, P = .005; HR 1.46, 95% CI 1.1-1.95, P = .009; respectively). Concentric LVH was independently associated with a decreased risk for mortality compared to normal LV geometry (HR 0.75, 95% CI 0.63-0.89, P = .001). Compared to concentric LVH, eccentric LVH was independently associated with a 33% increased risk for mortality (HR 1.33, 95% CI 1.11-1.60, P = .002).

CONCLUSIONS

Mild concentric LVH confers a protective effect among patients with severe aortic stenosis undergoing TAVR. However, hypertrophy becomes maladaptive, and an increased baseline LVMI, eccentric pattern particularly, may be associated with all-cause mortality in this population.

Prognostic value of pre-procedural left ventricular strain for clinical events after transcatheter aortic valve implantation

Background

Transcatheter aortic valve implantation (TAVI) is an alternative therapy for surgically high-risk patients with severe aortic stenosis (AS). Although TAVI improves survival of patients with severe AS, the mechanism of this effect remains to be clarified. We investigated the effects of TAVI on left ventricular (LV) function and identified the predictive parameters for cardiac events after TAVI.

Methods and results

We studied 128 patients with severe symptomatic AS who underwent TAVI. Echocardiographic assessments were performed before and after TAVI. In addition to the conventional echocardiographic parameters such as LV ejection fraction (LVEF) and LV mass index (LVMI), the LV global longitudinal strain (GLS) and early diastolic peak strain rate (SR_E) using two-dimensional speckle tracking echocardiography were also evaluated. All patients were assessed for clinical events including major adverse cardiac events and stroke according to Valve Academic Research Consortium-2 criteria. GLS, early diastolic peak velocity (eʹ), aortic regurgitation (AR) severity, and SR_E were significantly improved after TAVI. Thirteen patients had an event during the observational period of 591 days (median). Patients with events had higher LVMI, more severe AR, and worse GLS compared to those without events. Furthermore, receiver-operating curve analysis revealed that GLS was the strongest predictor for clinical events (p = 0.009; area under the curve, 0.73).

Conclusion

Preoperative LV geometric deformation and dysfunction, as a consequence of the cumulative burden of pressure overload, improved after TAVI and could predict cardiac events after TAVI.

Shortening cardioplegic arrest time in patients undergoing combined coronary and valve surgery: results from a multicentre randomized controlled trial: the SCAT trial

OBJECTIVES

Combined coronary artery bypass grafting and valve surgery requires a prolonged period of cardioplegic arrest (CA) predisposing to myocardial injury and postoperative cardiac-specific complications. The aim of this trial was to reduce the CA time in patients undergoing combined coronary artery bypass grafting and valve surgery and assess if this was associated with less myocardial injury and related complications.

METHODS

Participants were randomized to (i) coronary artery bypass grafting performed on the beating heart with cardiopulmonary bypass support followed by CA for the valve procedure (hybrid) or (ii) both procedures under CA (conventional). To assess complications related to myocardial injury, we used the composite of death, myocardial infarction, arrhythmia, need for pacing or inotropes for >12 h. To assess myocardial injury, we used serial plasma troponin T and markers of metabolic stress in myocardial biopsies.

RESULTS

Hundred and sixty patients (80 hybrid and 80 conventional) were randomized. Mean age was 66.5 years and 74% were male. Valve procedures included aortic (61.8%) and mitral (33.1%) alone or in combination (5.1%). CA time was 16% lower in the hybrid group [median 98 vs 89 min, geometric mean ratio (GMR) 0.84, 95% confidence interval (CI) 0.77-0.93, P  = 0.0004]. Complications related to myocardial injury occurred in 131/160 patients (64/80 conventional, 67/80 hybrid), odds ratio 1.24, 95% CI 0.54-2.86, P  = 0.61. Release of troponin T was similar between groups (GMR 1.04, 95% CI 0.87-1.24, P  = 0.68). Adenosine monophosphate was 28% lower in the hybrid group (GMR 0.72, 95% CI 0.51-1.02, P  = 0.056).

CONCLUSIONS

The hybrid procedure reduced the CA time but myocardial injury outcomes were not superior to conventional approach.

TRIAL REGISTRATION

ISRCTN65770930.

Severe heart failure (NYHA Class IV) is associated with increased left ventricular mass index and short mitral deceleration time in severe aortic valve stenosis

BACKGROUND

In aortic valve stenosis (AS), congestive heart failure (CHF) is a well-established symptom that indicates the need for surgical aortic valve replacement (SAVR). However, it is difficult to judge whether CHF symptoms such as dyspnea are caused by severe AS or other conditions, especially in elderly persons with restricted mobility or other organ complications. It is important to identify objective and noninvasive parameters associated with severe CHF symptoms in severe AS.

METHODS

One hundred ninety-eight patients with severe AS without left ventricular (LV) dysfunction were retrospectively studied. CHF symptoms were classified by New York Heart Association (NYHA) functional class. Echo parameters were compared between NYHA I-III and NYHA IV.

RESULTS

Patients with NYHA IV (n = 40; 20%) were older (86 ± 6 vs 82 ± 8 years; P = .001) and had a larger LV mass index (LVMI) (157 ± 43 vs 114 ± 34 g/m² , P < .001), a higher transmitral flow velocity ratio (E/A) (1.31 ± 0.62 vs 0.93 ± 0.42; P = .001), a shorter deceleration time (DT) (202 ± 72 vs 286 ± 98 ms; P < .001), and a higher systolic pulmonary arterial pressure (SPAP) (44 ± 13 vs 35 ± 13 mm Hg; P < .001) than patients with NYHA I-III. On multivariable analysis, LVMI and DT were independently associated with NYHA IV. Receiver operating characteristic curve analysis identified LVMI ≥ 142 g/m² and DT ≤ 194 ms as the cutoff values associated with NYHA IV in patients with severe AS.

CONCLUSION

Left ventricular mass index and DT were independently associated with severe heart failure (NYHA IV). These echo parameters could be helpful to judge whether CHF symptoms are caused by severe AS.

Heterogeneity of systolic dysfunction in patients with severe aortic stenosis and preserved ejection fraction

BACKGROUND AND AIM

Left ventricular (LV) systolic strain has been shown to be an early marker of LV dysfunction in patients with severe aortic stenosis (AS) despite preserved ejection fraction (EF). Echocardiography has provided useful data on regional LV strain patterns, but is not as sensitive as magnetic resonance imaging (MRI). No prior studies have used MRI-based strain analysis to characterize regional three-dimensional strain in patients with severe AS.

METHODS

Twelve patients with severe AS and preserved EF underwent MRI-based multiparametric strain analysis. Circumferential and longitudinal strain values were calculated at individual points throughout the LV and analyzed in 12 discrete regions. Strain values were compared to a database of normal controls.

RESULTS

Compared to control patients, circumferential strain in AS patients was significantly reduced at the base (P = 0.002), mid (P = 0.042), and inferior walls (P < 0.001). Longitudinal strain was significantly reduced at the base (P < 0.001), mid (P < 0.001), anterior (P < 0.001), and septal (P < 0.001) walls. Among patients with AS, there was heterogeneity in the location and severity of abnormalities in circumferential and longitudinal strains despite the presence of a preserved EF and lack of prior myocardial infarction.

CONCLUSIONS

LV systolic strain is significantly impaired in patients with AS and preserved EF compared to healthy volunteers. Abnormalities in circumferential and longitudinal strains were heterogeneously distributed across the LV of patients with AS, allowing us to identify sentinel regions that may reflect the earliest signs of developing LV dysfunction.

Early Left and Right Ventricular Response to Aortic Valve Replacement

BACKGROUND

The immediate effect of aortic valve replacement (AVR) for aortic stenosis on perioperative myocardial function is unclear. Left ventricular (LV) function may be impaired by cardioplegia-induced myocardial arrest and ischemia-reperfusion injury, especially in patients with LV hypertrophy. Alternatively, LV function may improve when afterload is reduced after AVR. The right ventricle (RV), however, experiences cardioplegic arrest without benefiting from improved loading conditions. Which of these effects on myocardial function dominate in patients undergoing AVR for aortic stenosis has not been thoroughly explored. Our primary objective is thus to characterize the effect of intraoperative events on LV function during AVR using echocardiographic measures of myocardial deformation. Second, we evaluated RV function.

METHODS

In this supplementary analysis of 100 patients enrolled in a clinical trial (NCT01187329), 97 patients underwent AVR for aortic stenosis. Of these patients, 95 had a standardized intraoperative transesophageal echocardiographic examination of systolic and diastolic function performed before surgical incision and repeated after chest closure. Echocardiographic images were analyzed off-line for global longitudinal myocardial strain and strain rate using 2D speckle-tracking echocardiography. Myocardial deformation assessed at the beginning of surgery was compared with the end of surgery using paired t tests corrected for multiple comparisons.

RESULTS

LV volumes and arterial blood pressure decreased, and heart rate increased at the end of surgery. Echocardiographic images were acceptable for analysis in 72 patients for LV strain, 67 for LV strain rate, and 54 for RV strain and strain rate. In 72 patients with LV strain images, 9 patients required epinephrine, 22 required norepinephrine, and 2 required both at the end of surgery. LV strain did not change at the end of surgery compared with the beginning of surgery (difference: 0.7 [97.6% confidence interval, -0.2 to 1.5]%; P = 0.07), whereas LV systolic strain rate improved (became more negative) (-0.3 [-0.4 to -0.2] s; P < 0.001). In contrast, RV systolic strain worsened (became less negative) at the end of surgery (difference: 4.6 [3.1 to 6.0]%; P < 0.001) although RV systolic strain rate was unchanged (0.0 [97.6% confidence interval, -0.1 to 0.1]; P = 0.83).

CONCLUSIONS

LV function improved after replacement of a stenotic aortic valve demonstrated by improved longitudinal strain rate. In contrast, RV function, assessed by longitudinal strain, was reduced.

Hyperinsulinemic Normoglycemia Does Not Meaningfully Improve Myocardial Performance during Cardiac Surgery: A Randomized Trial

BACKGROUND

Glucose-insulin-potassium (GIK) administration during cardiac surgery inconsistently improves myocardial function, perhaps because hyperglycemia negates the beneficial effects of GIK. The hyperinsulinemic normoglycemic clamp (HNC) technique may better enhance the myocardial benefits of GIK. The authors extended previous GIK investigations by (1) targeting normoglycemia while administering a GIK infusion (HNC); (2) using improved echocardiographic measures of myocardial deformation, specifically myocardial longitudinal strain and strain rate; and (3) assessing the activation of glucose metabolic pathways.

METHODS

A total of 100 patients having aortic valve replacement for aortic stenosis were randomly assigned to HNC (high-dose insulin with concomitant glucose infusion titrated to normoglycemia) versus standard therapy (insulin treatment if glucose >150 mg/dl). The primary outcomes were left ventricular longitudinal strain and strain rate, assessed using speckle-tracking echocardiography. Right atrial tissue was analyzed for activation of glycolysis/pyruvate oxidation and alternative metabolic pathways.

RESULTS

Time-weighted mean glucose concentrations were lower with HNC (127 ± 19 mg/dl) than standard care (177 ± 41 mg/dl; P < 0.001). Echocardiographic data were adequate in 72 patients for strain analysis and 67 patients for strain rate analysis. HNC did not improve myocardial strain, with an HNC minus standard therapy difference of -1.2% (97.5% CI, -2.9 to 0.5%; P = 0.11). Strain rate was significantly better, but by a clinically unimportant amount: -0.16 s (-0.30 to -0.03 s; P = 0.007). There was no evidence of increased glycolytic, pyruvate oxidation, or hexosamine biosynthetic pathway activation in right atrial samples (HNC, n = 20; standard therapy, 22).

CONCLUSION

Administration of glucose and insulin while targeting normoglycemia during aortic valve replacement did not meaningfully improve myocardial function.

Outcome of Left-Sided Cardiac Remodeling in Severe Aortic Stenosis Patients Undergoing Transcatheter Aortic Valve Implantation

Left-sided cardiac remodeling in patients with severe aortic stenosis (AS) was associated with improved outcome; however, there are scarce data on remodeling process after transcatheter aortic valve implantation (TAVI). We sought to describe the remodeling process in patients with severe AS who underwent TAVI. Echocardiographic data were systematically collected at baseline, 30 days, 6 months, and 1 year, from a cohort of 333 patients who underwent TAVI. Patients were categorized according to left ventricular mass index (LVMi) and relative wall thickness (RWT) to the following geometries: (1) normal; (2) concentric remodeling; (3) concentric hypertrophy; and (4) eccentric hypertrophy. Reverse remodeling (partial or complete) was defined as normalization of LVMi and/or RWT and adverse remodeling as an increase in LVMi and/or RWT. The longitudinal change in LVMi and left atrial diameter index (LADi) was assessed using mixed models. Reverse LV remodeling at 1-year was observed in 24% of patients with available echo at follow-up, whereas 17% of patients had adverse remodeling at 1-year follow-up. This was especially noted in patients with normal geometry at baseline. Interestingly, LV reverse remodeling was not accompanied by a reduction in left atrial diameter. In conclusion, TAVI reverse ventricular remodeling and LV hypertrophy induced by aortic stenosis; however, this reversal is incomplete in most patients at 1-year and not followed by change in left atrial dimensions. Whether this favorable remodeling may impact clinical outcome needs to be further elucidated.

Early regression of severe left ventricular hypertrophy after transcatheter aortic valve replacement is associated with decreased hospitalizations

OBJECTIVES

This study sought to examine the relationship between left ventricular mass (LVM) regression and clinical outcomes after transcatheter aortic valve replacement (TAVR).

BACKGROUND

LVM regression after valve replacement for aortic stenosis is assumed to be a favorable effect of LV unloading, but its relationship to improved clinical outcomes is unclear.

METHODS

Of 2,115 patients with symptomatic aortic stenosis at high surgical risk receiving TAVR in the PARTNER (Placement of Aortic Transcatheter Valves) randomized trial or continued access registry, 690 had both severe LV hypertrophy (left ventricular mass index [LVMi] ≥ 149 g/m(2) men, ≥ 122 g/m(2) women) at baseline and an LVMi measurement at 30-day post-TAVR follow-up. Clinical outcomes were compared for patients with greater than versus lesser than median percentage change in LVMi between baseline and 30 days using Cox proportional hazard models to evaluate event rates from 30 to 365 days.

RESULTS

Compared with patients with lesser regression, patients with greater LVMi regression had a similar rate of all-cause mortality (14.1% vs. 14.3%, p = 0.99), but a lower rate of rehospitalization (9.5% vs. 18.5%, hazard ratio [HR]: 0.50, 95% confidence interval [CI]: 0.32 to 0.78; p = 0.002) and a lower rate of rehospitalization specifically for heart failure (7.3% vs. 13.6%, p = 0.01). The association with a lower rate of rehospitalization was consistent across subgroups and remained significant after multivariable adjustment (HR: 0.53, 95% CI: 0.34 to 0.84; p = 0.007). Patients with greater LVMi regression had lower B-type natriuretic peptide (p = 0.002) and a trend toward better quality of life (p = 0.06) at 1-year follow-up than did those with lesser regression.

CONCLUSIONS

In high-risk patients with severe aortic stenosis and severe LV hypertrophy undergoing TAVR, those with greater early LVM regression had one-half the rate of rehospitalization over the subsequent year compared to those with lesser regression.

Effects of levosimendan in patients with left ventricular hypertrophy undergoing aortic valve replacement

BACKGROUND

Left ventricular hypertrophy is associated with adverse outcomes, including death, during cardiac surgery. This may be facilitated by an increased oxygen demand and diastolic dysfunction. Levosimendan augments haemodynamics without further oxygen consumption and improves echocardiographic indices of diastolic dysfunction. This study aimed to describe the haemodynamic effects of short-term pre- and intra-operative levosimendan infusion including advanced echocardiographic measures of diastolic and systolic heart function.

METHODS

The study was randomised, double-blinded and placebo-controlled performed at a single-centre university hospital. Patients with left ventricular hypertrophy and ejection fraction > 45% scheduled for single procedure aortic valve replacement were included and randomised to infusion of either levosimendan 0.1 μg/kg/min or placebo from 4 h before anaesthesia to the end of surgery. Outcome measures were echocardiographic indices of left ventricular diastolic function: E/e' (primary endpoint), e', e'/a' and indices of systolic function: longitudinal strain, ejection fraction and s'. Patients were followed until 6 months after surgery. In addition, invasive haemodynamic measures were obtained perioperatively.

RESULTS

The trial was prematurely terminated due to an overall high incidence of post-operative atrial fibrillation (15/20, P = 0.002) after inclusion of 20 patients. The relative decrease in perioperative cardiac index was lower (P = 0.016) in the levosimendan group. There was no difference in E/e', and similar results were found for all measures of systolic function.

CONCLUSION

Short-term levosimendan caused a transient relative increase in cardiac index, but no effect was seen on the first post-operative day and up to 6 months post-operatively with indices of systolic and diastolic heart function.

Multicentre double-blind randomized controlled trial of perhexiline as a metabolic modulator to augment myocardial protection in patients with left ventricular hypertrophy undergoing cardiac surgery

OBJECTIVES

Patients undergoing cardiac surgery require adequate myocardial protection. Manipulating myocardial metabolism may improve the extent of myocardial protection. Perhexiline has been shown to be an effective anti-anginal agent due to its metabolic modulation properties by inhibiting the uptake of free fatty acids into the mitochondrion, and thereby promoting a more efficient carbohydrate-driven myocardial metabolism. Metabolic modulation may augment myocardial protection, particularly in patients with left ventricular hypertrophy (LVH) known to have a deranged metabolic state and are at risk of poor postoperative outcomes. This study aimed to evaluate the role of perhexiline as an adjunct in myocardial protection in patients with LVH secondary to aortic stenosis (AS), undergoing an aortic valve replacement (AVR).

METHODS

In a multicentre double-blind randomized controlled trial of patients with AS undergoing AVR ± coronary artery bypass graft surgery, patients were randomized to preoperative oral therapy with either perhexiline or placebo. The primary end point was incidence of inotrope use to improve haemodynamic performance due to a low cardiac output state during the first 6 h of reperfusion, judged by a blinded end points committee. Secondary outcome measures included haemodynamic measurements, electrocardiographic and biochemical markers of new myocardial injury and clinical safety outcome measures.

RESULTS

The trial was halted early on the advice of the Data Safety and Monitoring Board. Sixty-two patients were randomized to perhexiline and 65 to placebo. Of these, 112 (54 perhexiline and 48 placebo) patients received the intervention, remained in the trial at the time of the operation and were analysed. Of 110 patients who achieved the primary end point, 30 patients (16 perhexiline and 14 placebo) had inotropes started appropriately; there was no difference in the incidence of inotrope usage OR of 1.65 [confidence interval (CI): 0.67-4.06] P = 0.28. There was no difference in myocardial injury as evidenced by electrocardiogram odds ratio (OR) of 0.36 (CI: 0.07-1.97) P = 0.24 or postoperative troponin release. Gross secondary outcome measures were comparable between the groups.

CONCLUSIONS

Perhexiline as a metabolic modulator to enhance standard myocardial protection does not provide an additional benefit in haemodynamic performance or attenuate myocardial injury in the hypertrophied heart secondary to AS. The role of perhexiline in cardiac surgery is limited.

Relation of right ventricular mass and volume to functional health status in repaired tetralogy of Fallot

After repair of tetralogy of Fallot, right ventricular (RV) mass and mass:volume ratio may reflect RV remodeling and adverse outcomes. This study aimed to evaluate the relation of RV mass to functional health status and subsequent adverse RV remodeling and to determine whether RV mass measurement in systole could improve reproducibility. In 53 patients with tetralogy of Fallot (median 29 years old) who previously underwent cardiovascular magnetic resonance and completed the Short Form 36, version 2 (Optum, Eden Prairie, MN), short-axis images were analyzed for RV end-diastolic volume and diastolic and systolic mass, indexed to body surface area. The most recent subsequent cardiovascular magnetic resonance study (before pulmonary valve or conduit replacement) was evaluated for change in RV end-diastolic volume and ejection fraction. Diastolic indexed mass ≥37.3 g/m(2) (odds ratio 7.6, p = 0.02) predicted decreased general health scores. In patients with normal RV ejection fraction, indexed mass correlated with Physical Component Summary and general health scores. RV diastolic mass:volume ratio >0.2 had a strong association with subsequent increase in RV end-diastolic volume (odds ratio 26.1, p = 0.002). Systolic RV mass measurement had excellent correlation with diastolic measurement (r = 0.97, p <0.0001), but did not improve intraobserver or interobserver variability. In conclusion, RV mass relates to functional health status and adverse RV remodeling and can be measured with good reproducibility. RV mass should be routinely evaluated in this population and is best measured in diastole; further study is necessary to evaluate longitudinal changes in functional health status and RV parameters.

Myocardial injury following aortic valve replacement for severe aortic stenosis: risk factor of postoperative myocardial injury and its impact on long-term outcomes

Background

As hypertrophied myocardium predisposes the patient to decreased tolerance to ischemia and increased reperfusion injury, myocardial protection is of utmost importance in patients undergoing aortic valve replacement (AVR) for severe aortic valve stenosis (AS).

Methods

Consecutive 314 patients (mean age, 62.5±10.8 years; 143 females) with severe AS undergoing isolated AVR were included. Postoperative myocardial injury (PMI) was defined as 1) maximum postoperative creatinine kinase isoenzyme MB or troponin-I levels ≥10 times of reference, 2) postoperative low cardiac output syndrome or episodes of ventricular arrhythmia, or 3) left ventricular ejection fraction of less than 55% and decrease in left ventricle (LV) ejection fraction of more than 20% of the baseline value.

Results

There were 90 patients (28.7%) who developed PMI. There were five cases of early death (1.6%), all of whom had PMI. On multivariable analysis, the use of histidine-tryptophan-ketoglutarate (HTK) solution instead of blood cardioplegia (odds ratio [OR], 3.06; 95% confidence interval [CI], 1.63 to 5.77; p=0.001), greater LV mass (OR, 1.04; 95% CI, 1.01 to 1.07; p=0.007), and increased cardiac ischemic time (OR, 1.13; 95% CI, 1.05 to 1.22; p<0.001) were independent predictors for PMI. Patients who had PMI showed significantly inferior long-term survival than those without PMI (p=0.049).

Conclusion

PMI occurred in a considerable proportion of patients undergoing AVR for severe AS and was associated with poor long-term survival. HTK cardioplegia, higher LV mass, and longer cardiac ischemic duration were suggested as predictors of myocardial injury.

Left ventricular remodelling in aortic stenosis

Aortic stenosis (AS) is a progressive condition associated with high mortality if not treated. The hemodynamic effects of AS have serious implications for the left ventricle. In this review, we describe the responses of the left ventricle to AS by highlighting the process of adaptive remodelling, which begins as a beneficial compensatory mechanism but ultimately transitions to a maladaptive process with potentially irreversible consequences. We discuss the impact of left ventricular (LV) remodelling on diastolic and systolic function and on the development of symptoms. In addition, we review the adverse consequences of maladaptive LV remodelling on clinical outcomes before and after aortic valve replacement. The relative irreversibility of maladaptive remodelling and the clear relationship between its progression and clinical outcomes suggest a need to incorporate measures of LV performance beyond simply systolic function when deciding on the timing of valve replacement.

Risk factors for late valve-related mortality after aortic valve replacement in elderly patients

PURPOSE

Few recent studies have examined the long-term outcomes after aortic valve replacement (AVR), and independent predictors for long-term survival and valve-related mortality have not been elucidated.

METHODS

From January 1993 to December 2009, 132 elderly patients (≥70 years old) with aortic stenosis underwent AVR in our hospital. The patients comprised 61 men and71 women with a mean age of 76.1 ± 3.7 years. Patients with acute or old myocardial infarction, mitral valve disease, and re-do surgery were not included in this study. Risk factors for late valve-related mortality were examined.

RESULTS

The 5-year freedom from valve-related mortality rate was 89.6%. The following significant independent risk factors for late valve-related mortality were identified:increase in the preoperative left ventricular mass index (hazard ratio, 1.10 [per 10 g/m(2)];p = 0.040); lack of sinus rhythm (hazard ratio, 7.11; p = 0.005); peak transvalvular pressure gradient of <60 mmHg (hazard ratio, 7.48; p = 0.008).

CONCLUSION

In the elderly, AVR should be performed at an early stage of aortic stenosis, before an increase in the left ventricular mass index has occured, and while the heart rhythm is in sinus rhythm and the peak transvalvular pressure gradient is high.

Tricuspid regurgitation and right ventricular function after mitral valve surgery with or without concomitant tricuspid valve procedure

OBJECTIVES

To study the effect of mitral valve repair with or without concomitant tricuspid valve repair on functional tricuspid regurgitation and right ventricular function.

METHODS

From 2001 to 2007, 1833 patients with degenerative mitral valve disease, a structurally normal tricuspid valve, and no coronary artery disease underwent mitral valve repair, and 67 underwent concomitant tricuspid valve repair. Right ventricular function (myocardial performance index and tricuspid annular plane systolic excursion) was measured before and after surgery using transthoracic echocardiography for randomly selected patients with tricuspid regurgitation grade 0, 1+, and 2+ (100 patients for each grade) and 93 with grade 3+/4+, 393 patients in total.

RESULTS

In patients with mild (<3+) preoperative tricuspid regurgitation, mitral valve repair alone was associated with reduced tricuspid regurgitation and mild worsening of right ventricular function. Tricuspid regurgitation of 2+ or greater developed in fewer than 20%, and right ventricular function had improved, but not to preoperative levels, at 3 years. In patients with severe (3+/4+) preoperative tricuspid regurgitation, mitral valve repair alone reduced tricuspid regurgitation and improved right ventricular function; however, tricuspid regurgitation of 2+ or greater returned and right ventricular function worsened toward preoperative levels within 3 years. Concomitant tricuspid valve repair effectively eliminated severe tricuspid regurgitation and improved right ventricular function. Also, over time, tricuspid regurgitation did not return and right ventricular function continued to improve to levels comparable to that of patients with lower grades of preoperative tricuspid regurgitation.

CONCLUSIONS

In patients with mitral valve disease and severe tricuspid regurgitation, mitral valve repair alone was associated with improved tricuspid regurgitation and right ventricular function. However, the improvements were incomplete and temporary. In contrast, concomitant tricuspid valve repair effectively and durably eliminated severe tricuspid regurgitation and improved right ventricular function toward normal, supporting an aggressive approach to important functional tricuspid regurgitation.

Increased left ventricular myocardial mass is associated with arrhythmias after cardiac surgery

OBJECTIVES

The purpose of this study was to investigate whether patients with an elevated left ventricular mass index undergoing cardiac surgery were more likely to experience postoperative atrial and ventricular arrhythmias.

DESIGN

A retrospective analysis.

SETTING

A single tertiary care university hospital.

PARTICIPANTS

One thousand consecutive patients undergoing all types of adult cardiac surgery.

INTERVENTIONS

With institutional review board approval, intraoperative transesophageal echocardiographic images were reviewed by a single reviewer. The left ventricular mass index was calculated using the American Society of Echocardiography-recommended formula. Medical charts were reviewed for the occurrence and type of clinically significant postoperative arrhythmias.

MEASUREMENTS AND RESULTS

Of the patients who had an elevated left ventricular mass index, 47.6% (225/473) developed clinically significant postoperative arrhythmias compared with 38.3% (142/371) of patients with a normal left ventricular mass index (odds ratio [OR] = 1.46; 95% confidence interval [CI], 1.11-1.93; p = 0.007). In the multivariate analysis, this finding remained statistically significant, controlling for the effects of age, weight, sex, surgery type, left ventricular function, functional status, left atrial dimensions, and a history of atrial fibrillation (OR = 1.40; 95% CI, 1.03-1.90 per 100-g/m(2) increase in the left ventricular mass index). An increased left ventricular mass index was also an independent predictor of the separate or combined occurrence of atrial or ventricular arrhythmias.

CONCLUSIONS

An elevated left ventricular mass index was a strong independent predictor of clinically significant postoperative atrial and ventricular arrhythmias after adult cardiac surgery. Although prospective validation is required, targeting patients for arrhythmia prophylaxis therapy may be justified in patients with a left ventricular mass index >188 g/m(2).

Effects of phosphodiesterase type 5 inhibition on systemic and pulmonary hemodynamics and ventricular function in patients with severe symptomatic aortic stenosis

BACKGROUND

Pressure overload resulting from aortic stenosis causes maladaptive ventricular and vascular remodeling that can lead to pulmonary hypertension, heart failure symptoms, and adverse outcomes. Retarding or reversing this maladaptive remodeling and its unfavorable hemodynamic consequences has the potential to improve morbidity and mortality. Preclinical models of pressure overload have shown that phosphodiesterase type 5 inhibition is beneficial; however, the use of phosphodiesterase type 5 inhibitors in patients with aortic stenosis is controversial because of concerns about vasodilation and hypotension.

METHODS AND RESULTS

We evaluated the safety and hemodynamic response of 20 subjects with severe symptomatic aortic stenosis (mean aortic valve area, 0.7 ± 0.2 cm(2); ejection fraction, 60 ± 14%) who received a single oral dose of sildenafil (40 or 80 mg). Compared with baseline, after 60 minutes, sildenafil reduced systemic (-12%; P<0.001) and pulmonary (-29%; P=0.002) vascular resistance, mean pulmonary artery (-25%; P<0.001) and wedge (-17%; P<0.001) pressures, and increased systemic (13%; P<0.001) and pulmonary (45%; P<0.001) vascular compliance and stroke volume index (8%; P=0.01). These changes were not dose dependent. Sildenafil caused a modest decrease in mean systemic arterial pressure (-11%; P<0.001) but was well tolerated with no episodes of symptomatic hypotension.

CONCLUSIONS

This study shows for the first time that a single dose of a phosphodiesterase type 5 inhibitor is safe and well tolerated in patients with severe aortic stenosis and is associated with improvements in pulmonary and systemic hemodynamics resulting in biventricular unloading. These findings support the need for longer-term studies to evaluate the role of phosphodiesterase type 5 inhibition as adjunctive medical therapy in patients with aortic stenosis.

Subcoronary versus supracoronary aortic stenosis. An experimental evaluation

Background

Valvular aortic stenosis is the most common cause of left ventricular hypertrophy due to gradually increasing pressure work. As the stenosis develop the left ventricular hypertrophy may lead to congestive heart failure, increased risk of perioperative complications and also increased risk of sudden death. A functional porcine model imitating the pathophysiological nature of valvular aortic stenosis is very much sought after in order to study the geometrical and pathophysiological changes of the left ventricle, timing of surgery and also pharmacological therapy in this patient group.

Earlier we developed a porcine model for aortic stenosis based on supracoronary aortic banding, this model may not completely imitate the pathophysiological changes that occurs when valvular aortic stenosis is present including the coronary blood flow. It would therefore be desirable to optimize this model according to the localization of the stenosis.

Methods

In 20 kg pigs subcoronary (n = 8), supracoronary aortic banding (n = 8) or sham operation (n = 4) was preformed via a left lateral thoracotomy. The primary endpoint was left ventricular wall thickness; secondary endpoints were heart/body weight ratio and the systolic/diastolic blood flow ratio in the left anterior descending coronary. Statistical evaluation by oneway anova and unpaired t-test.

Results

Sub- and supracoronary banding induce an equal degree of left ventricular hypertrophy compared with the control group. The coronary blood flow ratio was slightly but not significantly higher in the supracoronary group (ratio = 0.45) compared with the two other groups (subcoronary ratio = 0.36, control ratio = 0.34).

Conclusions

A human pathophysiologically compatible porcine model for valvular aortic stenosis was developed by performing subcoronary aortic banding. Sub- and supracoronary aortic banding induce an equal degree of left ventricular hypertrophy. This model may be valid for experimental investigations of aortic valve stenosis but studies of left ventricular hypertrophy can be studied equally well by graduated constriction of the ascending aorta.

Acute kidney injury following cardiac surgery: role of perioperative blood pressure control

BACKGROUND/AIMS

Patients who develop acute kidney injury (AKI) after cardiac surgery continue to have a high mortality rate. Although factors that predispose to postoperative renal dysfunction have been identified, this knowledge has not been associated with a substantial reduction in the incidence of this serious adverse event.

METHODS

This review uses the existing literature to explore the relationship between AKI and perioperative blood pressure (BP) control in cardiac surgery patients. The results of recent novel analyses are introduced, and the implications of these studies for the management of cardiac surgery patients in the perioperative period are discussed.

RESULTS

Preexisting isolated systolic hypertension and wide pulse pressure increase the risk of postoperative renal dysfunction in the cardiac surgery population. New data suggest that BP lability (i.e., BP excursions outside an acceptable physiologic range) during cardiac surgery may also be an important predictor of subsequent renal dysfunction.

CONCLUSION

Recently published data suggest that perioperative BP lability influences both the risk of postoperative renal dysfunction and 30-day mortality. Future studies will determine whether the use of agents that allow improved BP control within a desirable range will reduce the incidence of postoperative AKI in cardiac surgery patients.

Preoperative levosimendan infusion in combined aortic valve and coronary bypass surgery

BACKGROUND

Cardiopulmonary bypass may have detrimental effects on intestinal function and decrease the concentrations of the active, long-acting metabolites of levosimendan, an inodilator used to improve cardiac function. The aim of this study was to evaluate the haemodynamic effects of preoperative levosimendan in patients undergoing high-risk cardiac surgery.

METHODS

Twenty-four patients were randomized to receive levosimendan (12 µg bolus followed by an infusion of 0.2 µg kg(-1) min(-1)) or a placebo 24 h before surgery. The inclusion criteria were left ventricular ejection fraction (LVEF) <50% or LV hypertrophy indicated by a wall thickness of >12 mm. Haemodynamics were recorded every hour for 24 h (pulmonary artery catheter) and daily until postoperative day 4 (whole-body impedance cardiography). Doppler echocardiography with tissue Doppler imaging was used to assess systolic and diastolic cardiac function.

RESULTS

The cardiac index (CI) and stroke volume index (SI) were higher in the levosimendan group (LG) for the 4 day postoperative period (P<0.05); on the fourth postoperative day, the CI was 3.0 litre m(-2) min(-1) in the LG compared with 2.4 litre m(-2) min(-1) in the control group (CG) and the SI was 30 vs 25 ml m(-2), respectively. The LVEF measured at baseline and on the fourth postoperative morning decreased in the CG, but was maintained in the LG.

CONCLUSIONS

Levosimendan improved haemodynamics compared with a placebo in patients undergoing high-risk cardiac surgery. The concentrations of levosimendan's metabolites were higher compared with earlier studies using perioperative dosing.

Glucose-insulin-potassium reduces the incidence of low cardiac output episodes after aortic valve replacement for aortic stenosis in patients with left ventricular hypertrophy: results from the Hypertrophy, Insulin, Glucose, and Electrolytes (HINGE) trial

BACKGROUND

Patients undergoing aortic valve replacement for critical aortic stenosis often have significant left ventricular hypertrophy. Left ventricular hypertrophy has been identified as an independent predictor of poor outcome after aortic valve replacement as a result of a combination of maladaptive myocardial changes and inadequate myocardial protection at the time of surgery. Glucose-insulin-potassium (GIK) is a potentially useful adjunct to myocardial protection. This study was designed to evaluate the effects of GIK infusion in patients undergoing aortic valve replacement surgery.

METHODS AND RESULTS

Patients undergoing aortic valve replacement for aortic stenosis with evidence of left ventricular hypertrophy were randomly assigned to GIK or placebo. The trial was double-blind and conducted at a single center. The primary outcome was the incidence of low cardiac output syndrome. Left ventricular biopsies were analyzed to assess changes in 5' adenosine monophosphate-activated protein kinase (AMPK), Akt phosphorylation, and protein O-linked β-N-acetylglucosamination (O-GlcNAcylation). Over a 4-year period, 217 patients were randomized (107 control, 110 GIK). GIK treatment was associated with a significant reduction in the incidence of low cardiac output state (odds ratio, 0.22; 95% confidence interval, 0.10 to 0.47; P=0.0001) and a significant reduction in inotrope use 6 to 12 hours postoperatively (odds ratio, 0.30; 95% confidence interval, 0.15 to 0.60; P=0.0007). These changes were associated with a substantial increase in AMPK and Akt phosphorylation and a significant increase in the O-GlcNAcylation of selected protein bands.

CONCLUSIONS

Perioperative treatment with GIK was associated with a significant reduction in the incidence of low cardiac output state and the need for inotropic support. This benefit was associated with increased signaling protein phosphorylation and O-GlcNAcylation. Multicenter studies and late follow-up will determine whether routine use of GIK improves patient prognosis.

A model for left ventricular hypertrophy enabling non-invasive assessment of cardiac function

OBJECTIVE

To develop a porcine model for Left Ventricular Hypertrophy (LVH) in which cardiac performance could be quantified non-invasively by Doppler ultrasound.

DESIGN

Sixteen 5 kg piglets were divided into two groups. In the first group (n=12) we performed an aortic banding and in the second group (n=4) a sham-operation. Endpoints were echo-assessed left ventricular midseptal and free-wall thickness, heart/body-weight ratio and cardiac myocyte diameter.

RESULTS

Free-wall thickness: 0.77+/-0.013 cm in the intervention group and 0.60+/-0.006 cm in the control group (p=0.015). Midseptal thickness: 0.79+/-0.015 cm in the intervention group and 0.58+/-0.010 cm in the control group (p=0.012). Heart/body-weight ratio: 7.73+/-0.970 in the intervention group and 6.23+/-0.430 in the control group (p=0.003). Cardiac myocyte diameter: 19.6+/-4.9 microm in the intervention group and 11.0+/-1.9 microm in the control group (p=0.000).

CONCLUSION

A chronic porcine model for LVH has been established in which Doppler ultrasound can be used to quantify cardiac function non-invasively.

Different characteristics of postoperative heart failure after surgery for aortic stenosis and coronary disease

OBJECTIVE

Postoperative heart failure (PHF) remains a major determinant of outcome after cardiac surgery. However, possible differences in characteristics of PHF after valve surgery and coronary surgery (CABG) have received little attention. Therefore, this issue was studied in patients undergoing aortic valve replacement (AVR) and CABG, respectively.

DESIGN

Three hundred and ninety-eight patients undergoing isolated AVR for aortic stenosis were compared with 398 patients, matched for age and sex, undergoing on-pump isolated CABG. Forty-five AVR and 47 CABG patients required treatment for PHF and these were studied in detail.

RESULTS

The AVR group had longer aortic cross-clamp time and higher rate of isolated right ventricular heart failure postoperatively. Myocardial ischemia during induction and perioperative myocardial infarction were more common in the CABG group. One-year mortality was 8.9% in the AVR group vs 25.5% in the CABG group (p = 0.05).

CONCLUSIONS

The incidence of PHF was similar in both groups but different characteristics were found. Isolated right ventricular failure and PHF precipitated by septicemia were more common in AVR patients. PHF was more clearly associated with myocardial ischemia and infarction in CABG patients, which could explain their less favorable survival.