Effective Orifice Area during Exercise in Bileaflet Mechanical Valve Prostheses.

BACKGROUND: The aims of this study were to investigate the evolution of the transprosthetic pressure gradient and effective orifice area (EOA) during dynamic bicycle exercise in bileaflet mechanical heart valves and to explore the relationship with exercise capacity. METHODS: Patients with bileaflet aortic valve replacement (n = 23) and mitral valve replacement (MVR; n = 16) prospectively underwent symptom-limited supine bicycle exercise testing with Doppler echocardiography and respiratory gas analysis. Transprosthetic flow rate, peak and mean transprosthetic gradient, EOA, and systolic pulmonary artery pressure were assessed at different stages of exercise. RESULTS: EOA at rest, midexercise, and peak exercise was 1.66 ± 0.23, 1.56 ± 0.30, and 1.61 ± 0.28 cm2, respectively (P = .004), in aortic valve replacement patients and 1.40 ± 0.21, 1.46 ± 0.27, and 1.48 ± 0.25 cm2, respectively (P = .160), in MVR patients. During exercise, the mean transprosthetic gradient and the square of transprosthetic flow rate were strongly correlated (r = 0.65 [P < .001] and r = 0.84 [P < .001] for aortic valve replacement and MVR, respectively), conforming to fundamental hydraulic principles for fixed orifices. Indexed EOA at rest was correlated with exercise capacity in MVR patients only (Spearman ρ = 0.68, P = .004). In the latter group, systolic pulmonary artery pressures during exercise were strongly correlated with the peak transmitral gradient (ρ = 0.72, P < .001). CONCLUSIONS: In bileaflet mechanical valve prostheses, there is no clinically relevant increase in EOA during dynamic exercise. Transprosthetic gradients during exercise closely adhere to the fundamental pressure-flow relationship. Indexed EOA at rest is a strong predictor of exercise capacity in MVR patients. This should be taken into account in therapeutic decision making and prosthesis selection in young and dynamic patients.

Mid-term results of leaflet augmentation in severe tricuspid functional tethering.

OBJECTIVES: Functional tricuspid regurgitation (FTR) is usually managed surgically using various types of annuloplasty. FTR has been reported to recur in up to 45% of patients, with severe leaflet tethering being an important risk factor for recurrence. The aim of this study is to report the clinical and echocardiographic mid-term results after leaflet augmentation in patients with FTR due to severe leaflet tethering. METHODS: From May 2008 to July 2014, 22 patients were found to have a severe FTR with a tethering height of at least 8 mm; all of them underwent leaflet augmentation: the anterior and part of the posterior leaflet were detached from the anterior annulus; a patch of fresh autologous pericardium was used to generously fill the gap between the anterior annulus and the detached leaflet. A 5/0 Pronova suture locked at every step was used to avoid any purse string effect. In 2 patients, the septal leaflet also needed to be augmented using a comparable technique. In all but one (annular calcification) patient, a semi-rigid ring annuloplasty was added. The mean age was 67.1 ± 13.7 years; it was a redo procedure in 12 cases (54.5%), 11 patients (50%) had right ventricle failure and 3 (23.1%) had renal failure. RESULTS: The median follow-up was 2.1 ± 1.9 years. Thirty-day and 4-year survival averaged at 81.1 ± 8.5 and 71.6 ± 9.8%, respectively. At 4 years, 84 ± 10.6% of the survivors were in NYHA class I or II and only 2 patients had a TR of ≥2 with a global freedom from TR ≥2 of 85.7 ± 13.2%. There was no reintervention. CONCLUSIONS: Tricuspid leaflet augmentation combined with annuloplasty is feasible and leads to excellent clinical and echocardiographical mid-term results even in the presence of severe leaflet tethering and right ventricular failure.

Anomalous Origin of the Circumflex Artery: An Underestimated Threat During Mitral Valve Operation.

Ischemic iatrogenic lesions can complicate surgical procedures on the mitral valve. One of the causative mechanisms is direct injury to or distortion of the circumflex coronary artery. The risk of damaging the circumflex coronary artery depends mainly on the proximity of that vessel to the posterior segment of the mitral annulus, and this varies from patient to patient. Herein, we report the case of an iatrogenic circumflex coronary artery lesion after mitral annuloplasty in a patient with an anomalous origin of the circumflex artery.

Is the air in Toronto, Rochester, and Cleveland different from that in London, Monaco, Leiden, Genk, Milan, and New York?

The tricuspid valve has been recently referred to as the "forgotten valve," because one now realizes that tricuspid regurgitation is bad for the patient and that reoperation for progressive tricuspid regurgitation after a left-sided valvular correction still carries a high mortality risk. However, the indication for concomitant tricuspid valve repair during a mitral valve repair procedure is still controversial, as illustrated by the reaction of Dr T. David to the presentation of Dr Chikwe and colleagues at the 2015 American Association for Thoracic Surgery meeting. One of the explanations for these divergent opinions could be that tricuspid regurgitation grading is largely unreliable because of the dependence of the right ventricle on the preload and of the discrepancy between clinical and hemodynamic data. Therefore, we need a parameter that does not depend on preload. An annular dilation of 40 mm or 21 mm/m(2) has been proposed and validated by many authors. The preoperative functional class also plays a major role. Tricuspid regurgitation is a progressive disease, but the presence of a concomitant mitral valve disease may aggravate annular dilation; therefore, the earlier we operate on the mitral valve, the less frequently patients will require concomitant tricuspid valve repair.

Mitral valve area during exercise after restrictive mitral valve annuloplasty: importance of diastolic anterior leaflet tethering.

BACKGROUND: Restrictive mitral valve annuloplasty (RMA) for secondary mitral regurgitation might cause functional mitral stenosis, yet its clinical impact and underlying pathophysiological mechanisms remain debated. OBJECTIVES: The purpose of our study was to assess the hemodynamic and clinical impact of effective orifice area (EOA) after RMA and its relationship with diastolic anterior leaflet (AL) tethering at rest and during exercise. METHODS: Consecutive RMA patients (n = 39) underwent a symptom-limited supine bicycle exercise test with Doppler echocardiography and respiratory gas analysis. EOA, transmitral flow rate, mean transmitral gradient, and systolic pulmonary arterial pressure were assessed at different stages of exercise. AL opening angles were measured at rest and peak exercise. Mortality and heart failure readmission data were collected for at least 20 months after surgery. RESULTS: EOA and AL opening angle were 1.5 ± 0.4 cm(2) and 68 ± 10°, respectively, at rest (r = 0.4; p = 0.014). EOA increased significantly to 2.0 ± 0.5 cm(2) at peak exercise (p < 0.001), showing an improved correlation with AL opening angle (r = 0.6; p < 0.001). Indexed EOA (EOAi) at peak exercise was an independent predictor of exercise capacity (maximal oxygen uptake, p = 0.004) and was independently associated with freedom from all-cause mortality or hospital admission for heart failure (p = 0.034). Patients with exercise EOAi <0.9 cm(2)/m(2) (n = 14) compared with ≥0.9 cm(2)/m(2) (n = 25) had a significantly worse outcome (p = 0.048). In multivariate analysis, AL opening angle at peak exercise (p = 0.037) was the strongest predictor of exercise EOAi. CONCLUSIONS: In RMA patients, EOA increases during exercise despite fixed annular size. Diastolic AL tethering plays a key role in this dynamic process, with increasing AL opening during exercise being associated with higher exercise EOA. EOAi at peak exercise is a strong and independent predictor of exercise capacity and is associated with clinical outcome. Our findings stress the importance of maximizing AL opening by targeting the subvalvular apparatus in future repair algorithms for secondary mitral regurgitation.

The role of extracellular matrix in age-related conduction disorders: a forgotten player?

Cardiovascular aging is a physiological process gradually leading to structural degeneration and functional loss of all the cardiac and vascular components. Conduction system is also deeply influenced by the aging process with relevant reflexes in the clinical side. Age-related arrhythmias carry significant morbidity and mortality and represent a clinical and economical burden. An important and unjustly unrecognized actor in the pathophysiology of aging is represented by the extracellular matrix (ECM) that not only structurally supports the heart determining its mechanical and functional properties, but also sends a biological signaling regulating cellular function and maintaining tissue homeostasis. At the biophysical level, cardiac ECM exhibits a peculiar degree of anisotropy, which is among the main determinants of the conductive properties of the specialized electrical conduction system. Age-associated alterations of cardiac ECM are therefore able to profoundly affect the function of the conduction system with striking impact on the patient clinical conditions. This review will focus on the ECM changes that occur during aging in the heart conduction system and on their translation to the clinical scenario. Potential diagnostic and therapeutical perspectives arising from the knowledge on ECM age-associated alterations are further discussed.

Mitral valvuloplasty: when the art of repair meets the biological science.

The majority of approaches currently described and practiced in mitral repair surgery result in the vertical immobilization of the posterior leaflet, with the anterior leaflet striving to produce an adequate coaptation. Despite the satisfactory hemodynamic outcome and disappearance of mitral regurgitation, this non-physiological situation results in a redistribution of forces within the mitral apparatus with an increased stress on the leaflets. Biological evidences are pointing at the ability of the valvular interstitial cells to actively respond to biomechanical changes, switching their phenotype and producing different patterns of extracellular matrix proteins. This biological event translates to changes in the anatomical and mechanical properties of the leaflets, leading to an increased stiffening and a susceptibility to develop calcification. These concepts find a clinical reflex in reports on the long-term thickening and calcification of the leaflets after mitral repair, and in the leaflets remodeling phenomena described in chronically dilated ventricles. The importance of respecting the physiological movement and dynamics of the leaflets when performing a valvuloplasty is underlined, and a potential pharmacological modulation of the aforementioned biological processes to ameliorate long-term results of the repair is hypothesized.

Pulmonary homograft endocarditis and aortic autograft failure after Ross procedure: a double stentless bioprosthesis approach.

The case is reported of a 38-year-old male patient with pulmonary homograft acute infective endocarditis and aortic root dilation that occurred 13 years after a Ross procedure for bicuspid aortic valve regurgitation. Aortic and pulmonary root replacements were performed, using a Freestyle stentless aortic root bioprosthesis in both cases, with excellent hemodynamics on postoperative echocardiography. In addition, preoperative systemic septic embolization had occurred despite an absence of left-sided endocarditis, presumably due to an intrapulmonary shunt. This case report demonstrates the feasibility of a double stentless bioprosthesis approach, and stresses the need to remain vigilant for septic embolization even in isolated right-sided endocarditis.

Myectomy and mitral repair through the left atrium in hypertrophic obstructive cardiomyopathy: the preferred approach for contemporary surgical candidates?

OBJECTIVE: Patients with hypertrophic obstructive cardiomyopathy due to diffuse hypertrophy extending to or below the papillary muscles are poor candidates for alcohol septal ablation and suboptimal candidates for transaortic septal myectomy. In addition, the outflow obstruction is often aggravated by an abnormal mitral valve and subvalvular apparatus. METHODS: We performed transatrial myectomy in 12 patients with diffuse hypertrophy, who were highly symptomatic despite maximal medical therapy. All had at least moderate mitral regurgitation and systolic anterior motion. The anterior mitral leaflet (AML) was detached from commissure to commissure, allowing an easy myectomy through this AML toward the base of the anterior papillary muscle, with mobility fully restored. The abnormal chordae from the septum to the anterior papillary muscle and AML were divided. The continuity of this AML was restored with augmentation using an autologous pericardial patch. The height of the posterior mitral leaflet was reduced and the repair completed using an oversized annuloplasty ring. RESULTS: The peak intraventricular gradients decreased spectacularly from 98.8 ± 6.29 to 19.2 ± 13.4 mm Hg (P < .001), and the systolic anterior motion and mitral regurgitation disappeared. One patient died of left ventricular diastolic dysfunction. All other patients left the hospital in New York Heart Association class I or II. CONCLUSIONS: We believe that this technique is preferable for patients with hypertrophic obstructive cardiomyopathy and diffuse hypertrophy extending to the midportion of the left ventricle or beyond. It results in disappearance of outflow tract gradients and allows correction of the mitral valve abnormality.

Functional impact of transmitral gradients at rest and during exercise after restrictive annuloplasty for ischemic mitral regurgitation.

OBJECTIVES: Restrictive mitral valve annuloplasty combined with coronary artery bypass grafting is the treatment of choice for ischemic mitral regurgitation. Postoperative functional mitral stenosis and its potential impact on functional capacity remain the object of debate. The aim of this study was to assess functional and hemodynamic outcome at rest and during exercise in a population with ischemic mitral regurgitation after a standardized restrictive mitral valve annuloplasty. METHODS: A total of 23 patients with ischemic mitral regurgitation who were previously treated with coronary artery bypass grafting and restrictive mitral valve annuloplasty underwent a semi-supine (bicycle) exercise test with Doppler echocardiography and ergospirometry. The surgical technique was identical in all patients, using a complete semi-rigid ring downsized by 2 sizes after measuring the height of the anterior mitral leaflet, to achieve a coaptation length of at least 8 mm. RESULTS: At a mean follow-up of 28 ± 15 months, mean transmitral gradients at rest and maximal exercise were 4.4 ± 1.8 mm Hg and 8.2 ± 4.2 mm Hg, respectively (P < .001). Transmitral gradients did not correlate with exercise capacity (maximal oxygen uptake) or pulmonary artery pressures. Patients with a resting mean gradient of 5 mm Hg or greater (n = 9) reached a significantly higher maximal oxygen uptake; however, they had a better ejection fraction and cardiac output at rest and reached a higher cardiac output at peak exercise. CONCLUSIONS: Transmitral gradients after restrictive mitral valve annuloplasty for ischemic mitral regurgitation did not correlate with functional capacity as measured by maximal oxygen uptake during semi-supine bicycle testing. Functional capacity and transmitral gradients are determined not only by the severity of mitral stenosis but also by hemodynamic factors, such as ejection fraction and cardiac output. Transmitral gradients should be interpreted with respect to patient hemodynamics and not necessarily be considered as detrimental for functional capacity.

Tricuspid annuloplasty concomitant with mitral valve surgery: effects on right ventricular remodeling.

OBJECTIVES: Tricuspid valve annuloplasty (TVP) has been advocated concomitantly with left-sided cardiac surgery in case of more than moderate tricuspid regurgitation (TR) or tricuspid annular dilation (TAD) (diameter >40 mm or 21 mm/m²) even in the absence of significant TR. Data on postoperative right ventricular (RV) remodeling are lacking in such patients. METHODS: Preoperative and postoperative echocardiography data from 45 consecutive TVP procedures, performed in mitral valve surgery in a single tertiary center, were retrospectively analyzed and compared with a propensity-matched control group of 33 procedures without concomitant TVP. RV function and geometry was analyzed by measuring RV size, fractional area change, and end-diastolic sphericity index (RVSI = long-axis length/short-axis width) and compared at baseline versus follow-up. RESULTS: At a mean follow-up of 5 months, a favorable change in RV geometry was observed in TVP patients (RVSI increased from 1.99 ± 0.33 to 2.21 ± 0.42; P = .001), whereas the opposite was observed in the control group (RVSI decreased from 2.34 ± 0.52 to 2.17 ± 0.13; P = .05). Only in control patients, indexed RV end-diastolic area increased significantly (P = .003). In TVP patients, when comparing patients with baseline more than moderate TR (n = 13) to patients with isolated TAD (n = 32), there was a significant decrease in RV end-diastolic area only in the group with more than moderate TR (from 12.9 ± 3.5 cm(2)/m(2) to 10.3 ± 1.9 cm(2)/m(2); P = .009). CONCLUSIONS: Adding TVP to mitral valve surgery in patients with more than moderate TR or TAD leads to favorable changes in RV geometry and prevents postoperative RV dilation. This is most pronounced in patients with more than moderate TR at baseline.

Clinical outcomes after tricuspid valve annuloplasty in addition to mitral valve surgery.

Current guidelines recommend tricuspid valve annuloplasty (TVP) together with mitral valve surgery in cases of tricuspid annulus dilation (≥40 mm) or functional tricuspid valve regurgitation >2/4. Baseline clinical and echocardiographic data of patients undergoing mitral valve surgery in a single tertiary care hospital between 2007 and 2010 were analyzed. Mortality and heart failure hospitalization data were collected and groups with or without TVP were compared. Patients with TVP (n=89) had similar baseline characteristics compared with patients without (n=86), except for lower right ventricular fractional area change and more concomitant aortic valve surgery. Mortality was higher in the TVP group at 30 days (14% vs 5%; P=.04), but the difference was no longer significant at the end of follow-up. More patients were hospitalized for heart failure in the TVP group (31% vs 17%; hazard ratio, 2.1; 95% confidence interval, 1.1-4.0; P=.05). Right ventricular sphericity index was the only preoperative parameter predicting death or heart failure hospitalizations. In conclusion, patients undergoing TVP in addition to mitral valve surgery are at high risk for early death or subsequent heart failure hospitalizations, which might be partly explained by more complex heart disease. The extent of preoperative right ventricular remodeling may be predictive of adverse outcomes.

Salvage extensive coronary thromboendarterectomy for a ruptured left anterior descending artery.

We describe a lifesaving emergent thromboendarterectomy of the entire left anterior descending artery in a 63-year old man. Four days earlier, he had undergone a coronary artery bypass grafting. The left anterior descending artery was not bypassed then due to severe diffuse disease and calcifications. After an uneventful recovery, syncope occurred during exercise. Emergency catheterization revealed patent grafts, but no flow over the left anterior descending artery. At rescue percutaneous coronary intervention, a perforation of the left anterior descending artery occurred, leading to cardiogenic shock. A successful thromboendarterectomy of the left anterior descending artery salvaged the patient's life.

Surgical patch angioplasty of the left main coronary artery.

Isolated ostial stenosis of the left main coronary artery (LMCA) is rare, occurring in <1% of the patients undergoing coronary angiography. Surgical patch angioplasty (SPA) offers an alternative to conventional coronary artery bypass grafting (CABG) in such cases and is advantageous in restoring more physiological myocardial perfusion, maintaining ostial patency and preserving conduit material. However, a number of early technical failures and high perioperative mortality have limited the generalized uptake of this procedure, and only recently have advances in myocardial protection and novel surgical approaches to the LMCA resulted in a resurgence of the technique. A systematic literature search identified 45 studies incorporating 478 patients undergoing SPA. A variety of patch materials were used, including the pericardium, saphenous vein and internal mammary and pulmonary arteries. Patients were followed up for a mean of 54.4 months. The 30-day mortality was 1.7% and cardiac specific mortality 3.3% at last follow-up. Encouragingly, 92.4% of reported cases (n = 182) showed complete angiographic patency at last follow-up. Our results indicate that SPA may be a viable alternative to CABG in the surgical management of isolated ostial LMCA stenosis. However, no randomized trials have been performed, and it is clear that careful patient selection is essential in minimizing morbidity and mortality in the short- and long-term. Further research is required to allow a direct comparison of SPA to techniques with a more substantial evidence base such as CABG and percutaneous coronary intervention, and to define the optimal patch graft material, elucidating that any beneficial effects arterial patches may have on long-term patency.

Survival benefit of multiple arterial grafting in a 25-year single-institutional experience: the importance of the third arterial graft.

OBJECTIVES: The long-term advantages of multiple arterial grafts, particularly a third arterial conduit, for coronary artery bypass (CABG) are not clear. This study was designed to test whether multiple arterial grafts would provide better long-term outcomes when compared with approaches using fewer arterial conduits. METHODS: Between 1985 and 1995, prospective data were collected for 588 patients undergoing isolated CABG at our institution. We examined long-term survival and freedom from cardiac death. The primary analysis compared patients receiving bilateral internal thoracic artery (BITA) vs. single ITA (SITA). In a subgroup analysis, BITA patients receiving a right gastroepiploic artery (RGEA) were compared with those receiving a saphenous vein graft (SVG) as a third conduit. Cox proportional hazard modelling was used to adjust for relevant confounders. The Kaplan-Meier method was used to create survival curves over the follow-up period. RESULTS: The mean age was 59 ± 9 years and 49% received BITA. Mean follow-up was 16.1 ± 5.4 years. Multivariable analysis revealed that overall survival [hazard ratio (HR): 0.74, P = 0.017] and cardiac survival (HR: 0.61, P = 0.004) was significantly improved in the presence of BITA compared with SITA. The survival at 10 and 20 years was 90.2 ± 3.4 and 56.9 ± 6.4% for the BITA vs. 82 ± 4.4 and 40.9 ± 6% for the SITA, respectively. In the subgroup of BITA patients, those receiving the RGEA as a third conduit had superior overall survival (HR: 0.41, P = 0.0032) and cardiac survival (HR: 0.18, P = 0.004) compared with those receiving an SVG. The survival at 10 and 20 years was 98.9 ± 2 and 68.9 ± 18% for the BITA/RGEA vs. 87.2 ± 4.6 and 50.3 ± 7% for the BITA/SVG, respectively. CONCLUSIONS: In a single-institution experience, the use of multiple arterial grafting is independently associated with superior outcomes. Furthermore, the use of a third arterial conduit (RGEA) targeted to the right coronary artery should be considered to improve long-term survival.

Management of mitral regurgitation during left ventricular reconstruction for ischemic heart failure.

OBJECTIVE: Remodeling of the left ventricle (LV) in ischemic cardiomyopathy frequently leads to functional mitral regurgitation (MR). The indication for correcting MR in patients undergoing LV reconstruction (LVR) is unclear. In this study, we evaluated our strategy of correcting MR≥grade 2+ by restrictive mitral annuloplasty (RMA) during LVR. METHODS: We studied 92 consecutive patients (76 men, mean age 61±10 years) who underwent LVR for ischemic heart failure (IHF). RMA was performed in all patients with MR≥grade 2+ on preoperative echocardiography and in patients who showed increased MR to ≥grade 2+ immediately after LVR. Patients were attributed to a RMA and no-RMA group, depending on whether or not concomitant RMA had been performed. Mean clinical and structured echocardiographic follow-up was 47±20 months and was 100% complete. RESULTS: In 38 out of 40 patients (95%) with preoperative MR≥grade 2+, concomitant RMA was planned and performed. In 17 out of 52 patients (33%) with MR

Augmentation of the posterior leaflet of the mitral valve.

The augmentation of mitral valve leaflets is mostly needed in rheumatic valve disease patients. The technical aspects of augmentation of the posterior leaflet by means of an autologous pericardial patch are described: the thickened and semi-rigid posterior leaflet is detached from the posterior annulus from commissure to commissure and augmented by an onlay patch of autologous pericardium which is incorporated using a continuous stitch-locked at each step-of Prolene or Pronova 5/0. The pitfall 'aortic cusp effect in diastole' is described as well as tips to prevent it.

Surgical angioplasty and unroofing technique for intramural coronary anomaly.

A malign intramural course of the left main coronary artery is a rare anatomical anomaly. Surgical repair is mandatory since the condition is associated with myocardial ischemic syndromes and sudden death. Unroofing the intramural part and reconstructing a neo-ostium is challenging if the neo-ostium is immediately adjacent to the intercoronary commissure as there is a risk of narrowing the newly created ostium. We report a case in which we performed a surgical angioplasty of the left main coronary artery in combination with unroofing of the intramural section and resuspension of the intercoronary commissure.