A Matched-Paired Comparative Analysis of the Hemodynamics of the Trifecta and Perimount Aortic Bioprostheses

BACKGROUND AND AIM OF THE STUDY

Current cohort studies comparing the Trifecta valve to alternative pericardial bioprostheses are limited by selection bias. The study aim was to determine if hemodynamics are improved after the aortic valve implantation of a Trifecta valve as compared to a standard pericardial valve, when evaluated using strict paired matching for specific key relevant confounders.

METHODS

Valve hemodynamics were compared in patients undergoing implantation with a Trifecta or Perimount valve matched for left ventricular outflow tract (LVOT) diameter, gender, age, body size, and days since surgery, using a 1:1 matched-paired cohort analysis (n = 20 per group).

RESULTS

Patients receiving a Trifecta valve had a larger increase in indexed stroke volume (SVi) relative to baseline compared to the Perimount patients (p = 0.013), in whom SVi was decreased. The mean transvalvular pressure gradient was lower in Trifecta patients despite the larger SVi (p = 0.02). The effective orifice area (EOA) and indexed EOA (EOAi) were significantly larger in Trifecta patients compared to Perimount patients (2.04 +/- 0.46 versus 1.77 +/- 0.45 cm2, p = 0.049; 1.10 +/- 0.22 versus 0.95 +/- 0.06 cm2/m2, p = 0.027, respectively), and there was a greater increase in EOA and EOAi from baseline (p = 0.010 for both). Severe prosthesis-patient mismatch (PPM) (EOAi < or = 0.65 cm2/m2) was seen in two (10%) of the Perimount cases, but in none of the patients with the Trifecta valve (p = 0.072).

CONCLUSION

Trifecta valve implantation is associated with a significant improvement in EOA and a decreased incidence of PPM as compared to the Perimount valve. The superior hemodynamic outcomes observed support consideration of this valve for aortic valve replacement, particularly in patients with a small LVOT at risk for PPM.

Limitations of free-form-text diagnostic requisitions as a tool for evaluating adherence to appropriate use criteria for transthoracic echocardiography

BACKGROUND

Monitoring the adherence to Appropriateness Use Criteria (AUC) has been identified as an important component for the accreditation of echocardiography laboratories. Referral requisitions are a logical tool to rapidly determine the appropriateness of transthoracic echocardiography (TTE) referrals, however data is lacking. We investigated whether standard free-form-text TTE referral requisitions can be used to evaluate AUC adherence.

METHODS

Consecutive TTE referral requisitions to the University of Ottawa Heart Institute echocardiography laboratory were reviewed over a four-week period. Indication on the requisition was matched with the relevant indication on the 2011 American College of Cardiology Foundation (ACCF) AUC. Requisitions that did not provide sufficient information to identify the relevant AUC indication were identified as inadequate. For inadequate requisitions, reason for the referral was clarified through medical records and referring physicians.

RESULTS

Of the 1303 requisitions, 26.2% did not provide adequate information to determine adherence to AUC, despite a non-adherence (inappropriate) rate of only 6.1% in the referral population. Indication for referral, physician specialty, outpatient status, and prior echocardiogram were independent predictors of inadequate requisitions (p < 0.001, respectively). The most common reasons for inadequate requisitions were a failure to report: 1) change in clinical status, 2) date of a prior echocardiogram, and 3) type and/or severity of a valve lesion. Inclusion of this information would have decreased the inadequacy rate by 56%.

CONCLUSION

In a large, academic echocardiography laboratory, over one quarter of free-form-text TTE requisitions are inadequate to evaluate AUC adherence. Structured requisition formats requiring AUC-relevant information are needed to facilitate the practical application of AUC in the echocardiography laboratory.

Pulmonary hypertension due to fibrosing mediastinitis treated successfully with stenting of pulmonary vein stenoses

We describe a patient with fibrosing mediastinitis after childhood histoplasmosis who presented with severe pulmonary hypertension secondary to pulmonary vein stenoses. Stenting of 2 stenosed pulmonary veins via a transseptal approach resulted in an immediate decrease in systolic pulmonary artery pressure from 90 to 68 mm Hg and improvement in dyspnea and cardiac index, which was sustained at 6 months. This case highlights the importance of routinely assessing the pulmonary veins during workup for pulmonary hypertension.

Echocardiographic Evaluation of Aortic Stenosis - Normal Flow and Low Flow Scenarios

The echocardiographic evaluation of the patient with aortic stenosis (AS) has evolved in recent years, beyond confirming the diagnosis and measuring the resting mean pressure gradient or valve area. New echocardiographic approaches have developed to address the clinical dilemmas related to discordant haemodynamic data, asymptomatic haemodynamically severe AS and low-flow, low-gradient AS in order to better evaluate the disease severity, enhance the risk stratification of patients and provide important prognostic information. This article reviews the echocardiographic evaluation of the AS patient and focuses on the echocardiographic assessment of the haemodynamic severity, the prediction of clinical outcome and the use of echocardiography to guide patient management in the presence of normal flow and low flow scenarios.

Effects of short-term continuous positive airway pressure on myocardial sympathetic nerve function and energetics in patients with heart failure and obstructive sleep apnea: a randomized study

BACKGROUND

Heart failure with reduced ejection fraction and obstructive sleep apnea (OSA), 2 states of increased metabolic demand and sympathetic nervous system activation, often coexist. Continuous positive airway pressure (CPAP), which alleviates OSA, can improve ventricular function. It is unknown whether this is due to altered oxidative metabolism or presynaptic sympathetic nerve function. We hypothesized that short-term (6-8 weeks) CPAP in patients with OSA and heart failure with reduced ejection fraction would improve myocardial sympathetic nerve function and energetics.

METHODS AND RESULTS

Forty-five patients with OSA and heart failure with reduced ejection fraction (left ventricular ejection fraction 35.8±9.7% [mean±SD]) were evaluated with the use of echocardiography and 11C-acetate and 11C-hydroxyephedrine positron emission tomography before and ≈6 to 8 weeks after randomization to receive short-term CPAP (n=22) or no CPAP (n=23). Work metabolic index, an estimate of myocardial efficiency, was calculated as follows: (stroke volume index×heart rate×systolic blood pressure÷Kmono), where Kmono is the monoexponential function fit to the myocardial 11C-acetate time-activity data, reflecting oxidative metabolism. Presynaptic sympathetic nerve function was measured with the use of the 11C-hydroxyephedrine retention index. CPAP significantly increased hydroxyephedrine retention versus no CPAP (Δretention: +0.012 [0.002, 0.021] versus -0.006 [-0.013, 0.005] min(-1); P=0.003). There was no significant change in work metabolic index between groups. However, in those with more severe OSA (apnea-hypopnea index>20 events per hour), CPAP significantly increased both work metabolic index and systolic blood pressure (P<0.05).

CONCLUSIONS

In patients with heart failure with reduced ejection fraction and OSA, short-term CPAP increased hydroxyephedrine retention, indicating improved myocardial sympathetic nerve function, but overall did not affect energetics. In those with more severe OSA, CPAP may improve cardiac efficiency. Further outcome-based investigation of the consequences of CPAP is warranted.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00756366.

Granulocyte colony-stimulating factor therapy for stem cell mobilization following anterior wall myocardial infarction: the CAPITAL STEM MI randomized trial

BACKGROUND

Small studies have yielded divergent results for administration of granulocyte colony-stimulating factor (G-CSF) after acute myocardial infarction. Adequately powered studies involving patients with at least moderate left ventricular dysfunction are lacking.

METHODS

Patients with left ventricular ejection fraction less than 45% after anterior-wall myocardial infarction were treated with G-CSF (10 μg/kg daily for 4 days) or placebo. After initial randomization of 86 patients, 41 in the placebo group and 39 in the G-CSF group completed 6-month follow-up and underwent measurement of left ventricular ejection fraction by radionuclide angiography.

RESULTS

Baseline and 6-week mean ejection fraction was similar for the G-CSF and placebo groups: 34.8% (95% confidence interval [CI] 32.6%-37.0%) v. 36.4% (95% CI 33.5%-39.2%) at baseline and 39.8% (95% CI 36.2%-43.4%) v. 43.1% (95% CI 39.2%-47.0%) at 6 weeks. However, G-CSF therapy was associated with a lower ejection fraction at 6 months relative to placebo (40.8% [95% CI 37.4%-44.2%] v. 46.0% [95% CI 42.7%-44.3%]). Both groups had improved left ventricular function, but change in left ventricular ejection fraction was lower in patients treated with G-CSF than in those who received placebo (5.7 [95% CI 3.4-8.1] percentage points v. 9.2 [95% CI 6.3-12.1] percentage points). One or more of a composite of several major adverse cardiac events occurred in 8 patients (19%) within each group, with similar rates of target-vessel revascularization.

INTERPRETATION

In patients with moderate left ventricular dysfunction following anterior-wall infarction, G-CSF therapy was associated with a lower 6-month left ventricular ejection fraction but no increased risk of major adverse cardiac events. Future studies of G-CSF in patients with left ventricular dysfunction should be monitored closely for safety.

TRIAL REGISTRATION

ClinicalTrials.gov, no. NCT00394498.

Altered myocardial glucose utilization and the reverse mismatch pattern on rubidium-82 perfusion/F-18-FDG PET during the sub-acute phase following reperfusion of acute anterior myocardial infarction

BACKGROUND

Reperfused myocardium post-acute myocardial infarction (AMI) may have altered metabolism with implications for therapy response and function recovery. We explored glucose utilization and the "reverse mismatch" (RMM) pattern (decreased F-18-fluorodeoxyglucose (FDG) uptake relative to perfusion) in patients who underwent mechanical reperfusion with percutaneous coronary intervention (PCI) for AMI.

METHODS AND RESULTS

Thirty-one patients with anterior wall AMI treated with acute reperfusion, with left ventricular ejection fraction ≤45%, underwent rest rubidium-82 (Rb-82) and FDG PET 2-10 days post-AMI. Resting echocardiograms were used to assess wall motion abnormalities. Significant RMM occurred in 15 (48%) patients and was associated with a shorter time to PCI of 2.9 hours (2.2, 13.3 hours) compared to patients without significant RMM: 11.4 hours (3.9, 22.4 hours) (P = .03). Within the peri-infarct regions, segments with significant RMM were more likely to have wall motion abnormalities (OR = 2.3 (1.1, 4.7), P = .02) compared to segments without significant RMM.

CONCLUSIONS

RMM is a common pattern on perfusion/FDG PET during the sub-acute phase following reperfusion of AMI and is associated with shorter times to PCI. Within the peri-infarct region, RMM occurs frequently and is more often associated with wall motion abnormalities than segments without RMM. Whether this represents a myocardial metabolic shift during the sub-acute phase of recovery warrants further study.

Comparison between transcatheter and surgical prosthetic valve implantation in patients with severe aortic stenosis and reduced left ventricular ejection fraction

BACKGROUND

Patients with severe aortic stenosis and reduced left ventricular ejection fraction (LVEF) have a poor prognosis with conservative therapy but a high operative mortality when treated surgically. Recently, transcatheter aortic valve implantation (TAVI) has emerged as an alternative to surgical aortic valve replacement (SAVR) for patients considered at high or prohibitive operative risk. The objective of this study was to compare TAVI and SAVR with respect to postoperative recovery of LVEF in patients with severe aortic stenosis and reduced LV systolic function.

METHODS AND RESULTS

Echocardiographic data were prospectively collected before and after the procedure in 200 patients undergoing SAVR and 83 patients undergoing TAVI for severe aortic stenosis (aortic valve area ≤1 cm(2)) with reduced LV systolic function (LVEF ≤50%). TAVI patients were significantly older (81±8 versus 70±10 years; P<0.0001) and had more comorbidities compared with SAVR patients. Despite similar baseline LVEF (34±11% versus 34±10%), TAVI patients had better recovery of LVEF compared with SAVR patients (ΔLVEF, 14±15% versus 7±11%; P=0.005). At the 1-year follow-up, 58% of TAVI patients had a normalization of LVEF (>50%) as opposed to 20% in the SAVR group. On multivariable analysis, female gender (P=0.004), lower LVEF at baseline (P=0.005), absence of atrial fibrillation (P=0.01), TAVI (P=0.007), and larger increase in aortic valve area after the procedure (P=0.01) were independently associated with better recovery of LVEF.

CONCLUSION

In patients with severe aortic stenosis and depressed LV systolic function, TAVI is associated with better LVEF recovery compared with SAVR. TAVI may provide an interesting alternative to SAVR in patients with depressed LV systolic function considered at high surgical risk.

Intermittent, noncyclic dysfunction of a mechanical aortic prosthesis by pannus formation

Mechanical aortic prosthesis dysfunction can result from thrombosis or pannus formation. Pannus formation usually restricts systolic excursion of the occluding disk, resulting in progressive stenosis of the aortic prosthesis. Intermittent dysfunction of a mechanical aortic prosthesis is usually ascribed to thrombus formation. We describe an unusual case of intermittent, noncyclic dysfunction of a mechanical aortic prosthesis due to pannus formation in the absence of systolic restriction of disk excursion that presented with intermittent massive aortic regurgitation, severe ischemia, and shock. Pannus formation should be considered as a potential cause of acute intermittent severe aortic regurgitation in a patient with a mechanical aortic prosthesis.

Man's best friend? Infective endocarditis due to Capnocytophaga canimorsus

Infective endocarditis caused by zoonotic microorganisms is an uncommon clinical entity. A 55-year-old man was diagnosed with endocarditis due to Capnocytophaga canimorsus, a commensal bacterium contained in the saliva of dogs, that involved the aortic and tricuspid valves and was complicated by a para-aortic valve abscess and aorta-to-right atrial fistula. The patient was successfully treated with antibiotic therapy and surgical intervention. C canimorsus endocarditis should be considered in patients with culture-negative endocarditis, particularly in immunosuppressed, asplenic or alcoholic individuals who have recently suffered a dog bite or have had close contact with dogs.

Predictors of Outcomes in Low-Flow, Low-Gradient Aortic Stenosis

Background— Patients with low-flow, low-gradient aortic stenosis have a poor prognosis with conservative therapy but a high operative mortality if treated surgically. Recently, we proposed a new index of aortic stenosis severity derived from dobutamine stress echocardiography, the projected aortic valve area at a normal transvalvular flow rate, as superior to other conventional indices to differentiate true-severe from pseudosevere aortic stenosis. The objective of this study was to identify the determinants of survival, functional status, and change in left ventricular ejection fraction during follow-up of patients with low-flow, low-gradient aortic stenosis.

Methods and Results— One hundred one patients with low-flow, low-gradient aortic stenosis (aortic valve area ≤1.2 cm 2 , left ventricular ejection fraction ≤40%, and mean gradient ≤40 mm Hg) underwent dobutamine stress echocardiography and an assessment of functional capacity using the Duke Activity Status Index. A subset of 72 patients also underwent a 6-minute walk test. Overall survival was 70±5% at 1 year and 57±6% at 3 years. After adjusting for age, gender, and the type of treatment (aortic valve replacement versus no aortic valve replacement), significant predictors of mortality during follow-up were a Duke Activity Status Index ≤20 ( P =0.0005) or 6-minute walk test distance ≤320 m ( P <0.0001, in the subset of 72 patients), projected aortic valve area at a normal transvalvular flow rate ≤1.2 cm 2 ( P =0.03), and peak dobutamine stress echocardiography left ventricular ejection fraction ≤35% ( P =0.03). More severe stenosis, defined as projected aortic valve area ≤1.2 cm 2 , was a predictor of mortality only in the no aortic valve replacement group. The Duke Activity Status Index, 6-minute walk test, and left ventricular ejection fraction improved significantly during follow-up in the aortic valve replacement group, but remained unchanged or decreased in the no aortic valve replacement group.

Conclusion— In patients with low-flow, low-gradient aortic stenosis, the most significant risk factors for poor outcome were (1) impaired functional capacity as measured by Duke Activity Status Index or 6-minute walk test distance; (2) more severe valve stenosis as measured by projected aortic valve area at a normal transvalvular flow rate; and (3) reduced peak stress left ventricular ejection fraction, a composite measure accounting for both resting left ventricular function and contractile reserve.

Acute and chronic effects of continuous positive airway pressure therapy on left ventricular systolic and diastolic function in patients with obstructive sleep apnea and congestive heart failure

BACKGROUND

Obstructive sleep apnea (OSA) may contribute to the pathogenesis of congestive heart failure (CHF). Nocturnal continuous positive airway pressure (CPAP) therapy can alleviate OSA and may have a role in the treatment of CHF patients.

OBJECTIVES

To investigate the acute and chronic effects of CPAP therapy on left ventricular systolic function, diastolic function and filling pressures in CHF patients with OSA.

METHODS

Twelve patients with stable CHF (New York Heart Association II or III, radionuclide ejection fraction lower than 40%) underwent overnight polysomnography to detect OSA. In patients with OSA (n=7), echocardiography was performed at baseline (awake, before and during acute CPAP administration) and after 6.9+/-3.3 weeks of nocturnal CPAP therapy. Patients without OSA (n=5) did not receive CPAP therapy, but underwent a baseline and follow-up echocardiogram.

RESULTS

In CHF patients with OSA, acute CPAP administration resulted in a decrease in stroke volume (44+/-15 mL versus 50+/-14 mL, P=0.002) and left ventricular ejection fraction ([LVEF] 34.8+/-5.0% versus 38.4+/-3.3%, P=0.006) compared with baseline, but no change in diastolic function or filling pressures (peak early diastolic mitral annular velocity [Ea]: 6.0+/-1.6 cm/s versus 6.3+/-1.6 cm/s, P not significant; peak early filling velocity to peak late filling velocity [E/A] ratio: 1.05+/-0.74 versus 1.00+/-0.67, P not significant; E/Ea ratio: 10.9+/-4.1 versus 11.3+/-4.1, P not significant). In contrast, chronic CPAP therapy resulted in a trend to an increase in stroke volume (59+/-19 mL versus 50+/-14 mL, P=0.07) and a significant increase in LVEF (43.4+/-4.8% versus 38.4+/-3.3%, P=0.01) compared with baseline, but no change in diastolic function or filling pressures (Ea: 6.2+/-1.2 cm/s versus 6.3+/-1.6 cm/s, P not significant; E/A ratio: 1.13+/-0.61 versus 1.00+/-0.67, P not significant; E/Ea ratio: 12.1+/-2.7 versus 11.3+/-4.1, P not significant). There was no change in left ventricular systolic function, diastolic function or filling pressures at follow-up in CHF patients without OSA.

CONCLUSIONS

Acute CPAP administration decreased stroke volume and LVEF in stable CHF patients with OSA. In contrast, chronic CPAP therapy for seven weeks improved left ventricular systolic function, but did not affect diastolic function or filling pressures. The potential clinical implications of the discrepant effects of CPAP therapy on left ventricular systolic and diastolic function in CHF patients with OSA warrant further study.

Myocardial blood flow in patients with low-flow, low-gradient aortic stenosis: differences between true and pseudo-severe aortic stenosis. Results from the multicentre TOPAS (Truly or Pseudo-Severe Aortic Stenosis) study

BACKGROUND

Impairment of myocardial flow reserve (MFR) in aortic stenosis (AS) with normal left ventricular function relates to the haemodynamic severity.

OBJECTIVES

To investigate whether myocardial blood flow (MBF) and MFR differ in low-flow, low-gradient AS depending on whether there is underlying true-severe AS (TSAS) or pseudo-severe AS (PSAS).

METHODS

In 36 patients with low-flow, low-gradient AS, dynamic [13N]ammonia PET perfusion imaging was performed at rest (n = 36) and during dipyridamole stress (n = 20) to quantify MBF and MFR. Dobutamine echocardiography was used to classify patients as TSAS (n = 18) or PSAS (n = 18) based on the indexed projected effective orifice area (EOA) at a normal flow rate of 250 ml/s (EOAI(proj )<or= or >0.55 cm(2)/m(2)).

RESULTS

Compared with healthy controls (n = 14), patients with low-flow, low-gradient AS had higher resting mean (SD) MBF (0.83 (0.21) vs 0.69 (0.09) ml/min/g, p = 0.001), reduced hyperaemic MBF (1.16 (0.31) vs 2.71 (0.50) ml/min/g, p<0.001) and impaired MFR (1.44 (0.44) vs 4.00 (0.91), p<0.001). Resting MBF and MFR correlated with indices of AS severity in low-flow, low-gradient AS with the strongest relationship observed for EOAI(proj) (r(s) = -0.50, p = 0.002 and r(s) = 0.61, p = 0.004, respectively). Compared with PSAS, TSAS had a trend to a higher resting MBF (0.90 (0.19) vs 0.77 (0.21) ml/min/g, p = 0.06), similar hyperaemic MBF (1.16 (0.31) vs 1.17 (0.32) ml/min/g, p = NS), but a significantly smaller MFR (1.19 (0.26) vs 1.76 (0.41), p = 0.003). An MFR <1.8 had an accuracy of 85% for distinguishing TSAS from PSAS.

CONCLUSIONS

Low-flow, low-gradient AS is characterised by higher resting MBF and reduced MFR that relates to the AS severity. The degree of MFR impairment differs between TSAS and PSAS and may be of value for distinguishing these entities.

Tricuspid Annular Systolic Velocity Predicts Maximal Oxygen Consumption During Exercise in Adult Patients with Repaired Tetralogy of Fallot

BACKGROUND

Many patients with repaired tetralogy of Fallot (TOF) have clinically important pulmonary regurgitation that can eventually lead to right ventricular (RV) dilatation and dysfunction and associated morbidity and mortality. Unfortunately, standard echocardiographic techniques to evaluate RV size and function can be inaccurate. Newer Doppler modalities such as Doppler tissue imaging (DTI) can detect subtle changes in myocardial velocities and may better identify subclinical RV dysfunction in these patients.

METHODS

A total of 25 patients with repaired TOF prospectively underwent complete echocardiographic assessment (including DTI) of the RV and cardiopulmonary stress testing to evaluate exercise capacity. Echocardiographic variables were compared with age- and sex-matched control subjects.

RESULTS

Patients with repaired TOF had significantly lower RV DTI indices compared with control subjects. In patients with repaired TOF, RV peak systolic velocity had a significant correlation with maximal oxygen consumption during exercise (r = 0.80, P < .001) and was the only independent predictor of maximal oxygen consumption on multivariate analysis (r = 0.80, P < .001).

CONCLUSION

DTI identifies abnormalities of RV systolic and diastolic function in patients with repaired TOF. Importantly, RV systolic velocity is predictive of exercise capacity in these patients.

B-type natriuretic peptide in low-flow, low-gradient aortic stenosis: relationship to hemodynamics and clinical outcome: results from the Multicenter Truly or Pseudo-Severe Aortic Stenosis (TOPAS) study

BACKGROUND

The prognostic value of B-type natriuretic peptide (BNP) is unknown in low-flow, low-gradient aortic stenosis (AS). We sought to evaluate the relationship between AS and rest, stress hemodynamics, and clinical outcome.

METHODS AND RESULTS

BNP was measured in 69 patients with low-flow AS (indexed effective orifice area < 0.6 cm2/m2, mean gradient < or = 40 mm Hg, left ventricular ejection fraction < or = 40%). All patients underwent dobutamine stress echocardiography and were classified as truly severe or pseudosevere AS by their projected effective orifice area at normal flow rate of 250 mL/s (effective orifice area < or = 1.0 cm2 or > 1.0 cm2). BNP was inversely related to ejection fraction at rest (Spearman correlation coefficient r(s)=-0.59, P<0.0001) and at peak stress (r(s)=-0.51, P<0.0001), effective orifice area at rest (r(s)=-0.50, P<0.0001) and at peak stress (r(s)=-0.46, P=0.0002), and mean transvalvular flow (r(s)=-0.31, P=0.01). BNP was directly related to valvular resistance (r(s)=0.42, P=0.0006) and wall motion score index (r(s)=0.36, P=0.004). BNP was higher in 29 patients with truly severe AS versus 40 with pseudosevere AS (median, 743 pg/mL [Q1, 471; Q3, 1356] versus 394 pg/mL [Q1, 191 to Q3, 906], P=0.012). BNP was a strong predictor of outcome. In the total cohort, cumulative 1-year survival of patients with BNP > or = 550 pg/mL was only 47+/-9% versus 97+/-3% with BNP < 550 (P<0.0001). In 29 patients who underwent valve replacement, postoperative 1-year survival was also markedly lower in patients with BNP > or = 550 pg/mL (53+/-13% versus 92+/-7%).

CONCLUSIONS

BNP is significantly higher in truly severe than pseudosevere low-gradient AS and predicts survival of the whole cohort and in patients undergoing valve replacement.