Hemodynamic performance of stented and stentless aortic bioprostheses

Geometric changes in aortic root replacement using Freestyle prosthesis

Background

The Medtronic Freestyle prosthesis has proven to be a promising recourse for aortic root replacement in various indications. The present study aims to evaluate clinical outcomes and geometric changes of the aorta after Freestyle implantation.

Methods

Between October 2005 and November 2020, the computed tomography angiography (CTA) data of 32 patients were analyzed in a cohort of 68 patients that underwent aortic root replacement using Freestyle prosthesis. The minimum and maximum diameters and areas of the aortic annulus, aortic root, ascending aorta, and the proximal aortic arch were measured at a plane perpendicular to the long axis of the aorta using 3D multiplanar reconstruction in both the preoperative (n = 32) and postoperative (n = 10) CTAs. Moreover, volumetric changes of the aortic root and ascending aorta were quantified.

Results

Mean age was 64.6 ± 10.6 years. Indications for surgery using Freestyle prosthesis were combined aortic valve pathologies, aortic aneurysm or dissection, and endocarditis, with concomitant surgery occurring in 28 out of 32 patients. In-hospital mortality was 18.6%.

Preoperative diameter and area measurements of the aortic annulus strongly correlated with the implanted valve size (p < 0.001). Bicuspid valve was present in 28.1% of the patients. Diameter and areas of the aortic root decreased after freestyle implantation, resulting in a reduction of the aortic root volume (45.6 ± 26.3 cm³ to 18.7 ± 4.5 cm³, p = 0.029). Volume of the aortic root and the ascending aorta decreased from 137.3 ± 65.2 cm³ to 54.5 ± 21.1 cm³ after Freestyle implantation (p = 0.023).

Conclusion

Implantation of the Freestyle prosthesis presents excellent results in restoring the aortic geometry. Preoperative CTA measurements are beneficial to the surgical procedure and valve selection and therefore, if available, should be considered in pre-operative planning.

Structural valve deterioration and mode of failure of stentless bioprosthetic valves

BACKGROUND

Aortic stentless bioprosthetic valve (SLBPV), either porcine or pericardial, minimizes transvalvular gradient and favors regression of left ventricular hypertrophy. The drawback consists of longer time for suturing. While structural valve deterioration (SVD) in stented porcine and pericardial BPVs has been extensively investigated, less information is available on SLBPVs.

MATERIAL AND METHODS

We studied 82 SLBPVs explants, either porcine (Toronto SPV, [St. Jude Medical, MN, USA], CryolifeO'Brien Model 300 and CryoLife-O'Brien [Cryolife International, GA, USA], BioCor PVS [St. Jude Medical, MN, USA] Prima and Prima Plus [Edwards Lifesciences Corp. One Edwards Way, CA, formerly Baxter Inc, CA, USA]) or pericardial ([Pericarbon Freedom and Freedom Solo [Sorin-Biomedica, S.p.A., Saluggia, Italy]).

RESULTS

By excluding cases with leak and endocarditis, we focused the investigation on 46 SLBPVs, which failed because of SVD. Gender was male in 29 (63%). Mean age of patients at time of implant was 59.8 years. Postoperative time of SVD was 115.0 months for porcine and 79.0 months for pericardial SLBPVs. Dysfunction requiring reoperation was mainly incompetence for porcine and stenosis for pericardial SLBPVs. Even pinpoint mineralization at the commissures resulted in sudden cusp tearing and incompetence. Cuspal atheromasia accounted for cusp tearing even in the absence of calcification. Mineralization showed progression with time in pericardial but not in porcine SLBPVs.

CONCLUSIONS

Tissue mineralization remains the nightmare also of SLBPVs, with the peculiar features of pinpoint calcific deposits at commissures, tearing and abrupt incompetence in porcine SLBPVs and of massive cuspal mineralization and stenosis in pericardial SLBPVs.

Hemodynamics and reverse remodeling associated with Mosaic, Perimount and Trifecta aortic bioprostheses

Introduction: The implantation rate of aortic bioprostheses is increasing. Their durability has improved to some extent over the years and they allow for future transcatheter valve-in-valve deployment. In the lack of long term follow up, their hemodynamic profile, i.e. transvalvular mean pressure gradient and effective orifice area indexed, and the associated left ventricular reverse remodeling indexed are useful surrogates for clinical outcomes. Areas covered: A systematic review of the literature was conducted by searching Medline, Cochrane, Scielo, Embase databases, and grey literature until July 2018 for articles that perform comparisons among the three most popular aortic bioprostheses. Six randomized and 12 non-randomized studies were included with 565 patients receiving a Mosaic, 1334 a Perimount and 557 a Trifecta valve. These articles are heterogeneous but they allow the meta-analytic comparison of the abovementioned outcomes. Expert opinion: Compared to the Perimount valve, the Mosaic is hemodynamically inferior, while the Trifecta is superior. Despite these statistically significant differences, the left ventricular mass regression indexed, that is indicative of reverse remodeling, was comparable in all groups. All patients were similarly benefited. The predilection among these valves is fueled by their hemodynamic profile but not supported by the comparable reverse remodeling.

To fly as a pilot after cardiac surgery

Aircrew are responsible for safe and reliable aircraft operations. Cardiovascular disease accounts for 50% of all pilot licences declined or withdrawn for medical reasons in Western Europe and is the most common cases of sudden incapacitation in flight. Aircrew retirement age is increasing (up to age 65) in a growing number of airlines and the burden of subclinical, but potentially significant, coronary atherosclerosis is unknown in qualified pilots above age 40. Safety considerations are paramount in aviation medicine, and the most dreaded cardiovascular complications are thromboembolic events and rhythm disturbances due to their potential for sudden incapacitation. In aviation, the current consensus risk threshold for an acceptable level of controlled risk of acute incapacitation is 1% (for dual pilot commercial operations), a percentage calculated using engineering principles to ensure the incidence of a fatal air accident is no greater than 1 per 107 h of flying. This is known as the '1% safety rule'. To fly as a pilot after cardiac surgery is possible; however, special attention to perioperative planning is mandatory. Choice of procedure is crucial for license renewal. Licensing restrictions are likely to apply and the postoperative follow-up requires a tight scheduling. The cardiac surgeon should always liaise and communicate with the pilot's aviation medicine examiner prior to and following cardiac surgery.

Non-coronary cardiac surgery and percutaneous cardiology procedures in aircrew

This manuscript focuses on the broad aviation medicine considerations that are required to optimally manage aircrew following non-coronary surgery or percutaneous cardiology interventions (both pilots and non-pilot aviation professionals). Aircrew may have pathology identified earlier than non-aircrew due to occupational cardiovascular screening and while aircrew should be treated using international guidelines, if several interventional approaches exist, surgeons/interventional cardiologists should consider which alternative is most appropriate for the aircrew role being undertaken; liaison with the aircrew medical examiner is strongly recommended prior to intervention to fully understand this. This is especially important in aircrew of high-performance aircraft or in aircrew who undertake aerobatics. Many postoperative aircrew can return to restricted flying duties, although aircrew should normally not return to flying for a minimum period of 6 months to allow for appropriate postoperative recuperation and assessment of cardiac function and electrophysiology.

Pulmonary hypertension in cardiac surgery

Pulmonary hypertension is an important prognostic factor in cardiac surgery associated with increased morbidity and mortality. With the aging population and the associated increase severity of illness, the prevalence of pulmonary hypertension in cardiac surgical patients will increase. In this review, the definition of pulmonary hypertension, the mechanisms and its relationship to right ventricular dysfunction will be presented. Finally, pharmacological and non-pharmacological therapeutic and preventive approaches will be presented.

Diagnostic evaluation of left-sided prosthetic heart valve dysfunction

Prosthetic heart valve (PHV) dysfunction is a rare, but potentially life-threatening, complication. In clinical practice, PHV dysfunction poses a diagnostic dilemma. Echocardiography and fluoroscopy are the imaging techniques of choice and are routinely used in daily practice. However, these techniques sometimes fail to determine the specific cause of PHV dysfunction, which is crucial to the selection of the appropriate treatment strategy. Multidetector-row CT (MDCT) can be of additional value in diagnosing the specific cause of PHV dysfunction and provides valuable complimentary information for surgical planning in case of reoperation. Cardiac magnetic resonance imaging (CMR) has limited value in the evaluation of biological PHV dysfunction. In this Review, we discuss the use of established imaging modalities for the detection of left-sided mechanical and biological PHV dysfunction and discuss the complementary role of MDCT in this context.

Intraoperative Hemodynamic Instability During and After Separation From Cardiopulmonary Bypass

Every year, more than 1 million patients worldwide undergo cardiac surgery. Because of the aging of the population, cardiac surgery will increasingly be offered to patients at a higher risk of complications. The consequence is a reduced physiological reserve and hence an increased risk of mortality. These issues will have a significant impact on future health care costs because the population undergoing cardiac surgery will be older and more likely to develop postoperative complications. One of the most dreaded complications in cardiac surgery is difficult separation from cardiopulmonary bypass (CPB). When separation from CPB is associated with right-ventricular failure, the mortality rate will range from 44% to 86%. Therefore, the diagnosis and the preoperative prediction of difficult separation from CPB will be crucial to improve the selection and care of patients and to prevent complications for this high-risk patient population.

Assessment of fluctuating velocities in disturbed cardiovascular blood flow: in vivo feasibility of generalized phase-contrast MRI

PURPOSE

To evaluate the feasibility of generalized phase-contrast magnetic resonance imaging (PC-MRI) for the noninvasive assessment of fluctuating velocities in cardiovascular blood flow.

MATERIALS AND METHODS

Multidimensional PC-MRI was used in a generalized manner to map mean flow velocities and intravoxel velocity standard deviation (IVSD) values in one healthy aorta and in three patients with different cardiovascular diseases. The acquired data were used to assess the kinetic energy of both the mean (MKE) and the fluctuating (TKE) velocity field.

RESULTS

In all of the subjects, both mean and fluctuating flow data were successfully acquired. The highest TKE values in the patients were found at sites characterized by abnormal flow conditions. No regional increase in TKE was found in the normal aorta.

CONCLUSION

PC-MRI IVSD mapping is able to detect flow abnormalities in a variety of human cardiovascular conditions and shows promise for the quantitative assessment of turbulence. This approach may assist in clarifying the role of disturbed hemodynamics in cardiovascular diseases.

Root Replacement Using Stentless Valves in the Small Aortic Root: A Propensity Score Analysis

BACKGROUND

Root replacement using a stentless bioprosthesis may be the optimal approach to avoid patient-prosthesis mismatch in patients with a small aortic root. Primary root replacement, however, is considered to be associated with increased surgical risk. We compared early outcome of full root replacement with a stentless bioprosthesis with that of aortic valve replacement with a stented bioprosthesis using propensity score-matching analysis.

METHODS

Of 231 patients undergoing elective, first-time aortic valve replacement with a small root (< or = 22 mm), 120 patients were selected using propensity score-matching analysis. They underwent either root replacement using a 23-mm stentless bioprosthesis (stentless group, n = 60) or supra-annular aortic valve replacement using a 21-mm stented bioprosthesis (stented group, n = 60). Preoperative characteristics and frequency of concomitant operations were identical.

RESULTS

Duration of operation (196 +/- 54 versus 174 +/- 49 minutes), cardiopulmonary bypass (112 +/- 36 versus 91 +/- 33 minutes), and aortic cross-clamping (76 +/- 21 versus 61 +/- 21 minutes) were significantly longer in the stentless group. However, the need for perioperative transfusion and the incidence of postoperative reexploration for bleeding (3% versus 8%) was lower, and ventilation time was shorter. Mean duration of intensive care and hospital stay were also significantly shorter (2.3 +/- 1.7 versus 4.0 +/- 3.9 days, 8.9 +/- 3.1 versus 12.4 +/- 5.7 days). In-hospital mortality was identical (5% each). No independent predictor for in-hospital mortality was identified.

CONCLUSIONS

Full root replacement using a stentless bioprosthesis does not increase postoperative morbidity or mortality of aortic valve replacement and may be advantageous in patients with a small aortic root.

Carpentier-Edwards PERIMOUNT Magna bioprosthesis: A stented valve with stentless performance?

OBJECTIVE

We designed this study to evaluate the early hemodynamic performance of the recently introduced Carpentier-Edwards PERIMOUNT Magna bioprosthesis (Edwards Lifesciences, Irvine, Calif) and compare it with those of the conventional Carpentier-Edwards PERIMOUNT stented bioprosthesis (Edwards Lifesciences) and Edwards Prima Plus porcine stentless bioprosthesis (Edwards Lifesciences).

METHODS

Sixty-three patients (>70 years old) were enrolled in this prospective, randomized study. At operation, once the annulus had been measured, the best size suitable was assessed for each of the three valves before random assignment. Transthoracic echocardiography was performed before discharge to evaluate early postoperative hemodynamic performances of the different valves implanted.

RESULTS

The best size suitable of Edwards Prima Plus (24.3 +/- 1.7 mm) was significantly superior to those of both the Carpentier-Edwards PERIMOUNT Magna (23.4 +/- 2.1 mm) and Carpentier-Edwards PERIMOUNT (22.4 +/- 1.8 mm). The best size suitable of the Carpentier-Edwards PERIMOUNT Magna, however, was significantly superior to that of the Carpentier-Edwards PERIMOUNT. Furthermore the best size suitable of the Carpentier-Edwards PERIMOUNT Magna was equal to the measured annulus in 55% of patients, as opposed to 25% for the Carpentier-Edwards PERIMOUNT (P < .001). Mean implanted labeled size of the Edwards Prima Plus was significantly higher than those of both the Carpentier-Edwards PERIMOUNT Magna and the Carpentier-Edwards PERIMOUNT (24.6 +/- 1.9 mm, 23.1 +/- 1.9 mm, and 22.5 +/- 1.8 mm, respectively). Early postoperative hemodynamic performance of the Carpentier-Edwards PERIMOUNT Magna, however, was superior to those of both the Edwards Prima Plus and the Carpentier-Edwards PERIMOUNT in both effective orifice area index (1.07 +/- 0.4 cm2/m2, 0.87 +/- 0.3 cm2/m2, and 0.80 +/- 0.2 cm2/m2, respectively) and mean peak gradient (20 +/- 6 mm Hg, 27 +/- 8 mm Hg, and 28 +/- 12 mm Hg, respectively).

CONCLUSION

The improved design of the recently introduced third-generation stented bioprosthesis Carpentier-Edwards PERIMOUNT Magna allows implantation of a significantly bigger valve than with the old generation. Furthermore, the improved hemodynamic performance of the Carpentier-Edwards PERIMOUNT Magna compares favorably with both the Carpentier-Edwards PERIMOUNT and the Edwards Prima Plus.

Left ventricular remodeling after pulmonary autograft aortic valve replacement: evaluation with color-Doppler echocardiography and magnetic resonance imaging

The superior hemodynamic performance of the pulmonary autograft in aortic position is expected to reflect complete regression of hypertrophy and improved ventricular function. We evaluated and compared early and midterm transthoracic color-Doppler echocardiography (TTE) and magnetic resonance imaging (MRI) assessment concerning left ventricular (LV) function, LV mass regression, and performance of the semilunar valves. A total of 42 consecutive patients, mean age 36 +/- 6 years (range 15 to 56 years), were studied. TTE and MRI were performed preoperatively, at discharge, and at 6 and 12 months postoperatively. Left ventricular diameters and function and LV wall thickness and mass were assessed. There was no early and one late postoperative death. Maximum and mean LV outflow gradients were significantly reduced (p = 0.0001 and p = 0.0001, respectively). There was a significant reduction in left ventricular mass to near normal for all patients (p = 0.001) seen after 6 months. This was paralleled by significant reductions in the interventricular septum and posterior wall thickness, but difference was slight during further follow-up. There was a strong correlation between the results obtained by TTE and MRI for LV mass and ejection fraction (r = 0.86 and 0. 87, respectively). The pulmonary autograft operation gives excellent results that are translated into greater, rapid, and near complete regression of LV hypertrophy. Magnetic resonance imaging is a sensitive and noninvasive methodology that provides reliable visualization and quantification of ventricular performance.