Roberto Scrofani

Posterior pericardial annuloplasty: a physicological correction?

Since the introduction of the annuloplasty ring, many attempts have been made to obtain a flexible ring that preserves the physiological motion of the mitral annulus. We experimented with a new technique using autologous pericardium to construct a more flexible ring. Twenty patients underwent mitral valve repair for degenerative disease and were treated by a posterior pericardial annuloplasty and the usual valvuloplasty procedures. A long strip of pericardium was prepared, marked with metal clips and rolled up in a tubular fashion with the serosal surface on the outside. The pericardial tube was apposed on the posterior annulus just beyond the commissures. No patient required early or late reoperation. Doppler analysis showed good valve function: 18 patients had no or mild, and 2 had moderate regurgitation. Transmitral flow indexes were nearly normal (MVA = 3.7 +/- 0.4 cm2; flow velocity peak = 1.06 +/- 0.2 m/s). Fluoroscopic examination was employed for assessing annular motion using the metal clips as radiopaque markers. Planimetry of the hemiarea showed a mild narrowing (mean 8.5% +/- 6.4%) of annular size during ventricular systole. There was a trend toward a systolic reduction of the anteroposterior diameter of the annulus. These findings demonstrate that the mitral orifice preserves its flexible properties after this type of annuloplasty. Posterior pericardial annuloplasty seems to be a physiological correction of annular dilatation in patients with degenerative disease.

Assessment of an aortosaphenous vein graft anastomotic device in coronary surgery: Clinical experience and early angiographic results

BACKGROUND Until now technologic evolution in coronary bypass surgery has focused on extracorporeal circulation, on operation without extracorporeal circulation, and on the exposure of the operative site. Recently a one-shot anastomotic device for the proximal anastomosis in coronary surgery was developed. We investigated whether the use of the aortic connector system (ACS) could facilitate the creation of aortosaphenous vein graft anastomoses in myocardial revascularization. METHODS From November 2000, 40 ACS devices were used in 36 consecutive patients (mean age 70.7 +/- 8.9 years); 12 patients (33.3%) underwent surgery on pump and 24 patients (66.6%) off pump; 50 distal anastomoses were performed. In all cases the connection with the ascending aorta was created before the distal anastomoses because of the necessity to slide the saphenous vein graft (SVG) over the vein transfer sheath. Intraoperative graft function was tested measuring blood flow by Doppler analysis. Postoperative evaluation of the anastomotic patency was carried out by early angiography in 34 patients (94.7%) but was excluded in 5 patients (5.3%) with extensive extracardiac vascular occlusive disease. RESULTS Of 38 AC (95%) evaluated, 36 (94.7%) functioned properly. The end-to-side proximal anastomosis without aortic clamping is instantaneous, the quality of anastomoses was highly rated, no additional stitches were required, and all coronary arteries could be reached. Intraoperative quantity flow was measured by Doppler analysis and all but one showed good flow. Early postoperative angiography demonstrated good patency of the grafts in all cases but 2 (5.3%). At 1-year follow-up, 1 patient died of stroke; all other patients remained free of symptoms and no reoperation was required. CONCLUSIONS The use of ACS makes end-to-side anastomosis rapid, effective, and reproducible while eliminating aortic cross clamping; it opens a new era in beating or nonbeating coronary surgery. Long-term results are mandatory to confirm our favorable preliminary results.

Mitral Valve Remodeling: Long-Term Results With Posterior Pericardial Annuloplasty

BACKGROUND We studied the long-term results of a technique of mitral annuloplasty using autologous pericardium. METHODS Between June 1989 and December 1994, 113 mitral valvuloplasties were performed for myxomatous degenerative disease. Repair of isolated anterior leaflet prolapse was performed in 26 patients (23%), posterior leaflet prolapse in 38 (33.6%), and prolapse of both leaflets in 49 (43.4%). Posterior pericardial annuloplasty was performed in all patients. In 20 patients, the pericardial graft was marked with metal clips for postoperative cinefluoroscopic assessment of annulus motion. RESULTS The operative mortality rate was 2.7% (3/113). One patient died of myocardial infarction and 2 of low cardiac output syndrome. One patient required replacement of the mitral valve 2 days after operation because of dehiscence of the annular plication. Follow-up (average length, 32.41 +/- 20.09 months; range 1 to 71 months) was 97% complete and revealed good clinical and functional results: 95 patients (84.1%) were in New York Heart Association class I and had no regurgitation or only mild residual regurgitation. Postoperative transmitral flow indices were almost normal (mitral valve area = 3.7 +/- 0.4 cm2; peak flow velocity = 1.06 +/- 0.2 m/s). Only 3 patients had reoperation within 3 years (actuarial 5-year reoperation-free rate, 89.7%) and event-free survival at 5 years was 91%. In patients with metal clips marking autologous pericardium, planimetry of the area derived by fluoroscopic examination showed systolic narrowing of annulus size (8.5% +/- 6.4%; p < 0.01) and a slight systolic fall in the anteroposterior diameter of the annulus contour (5.9% +/- 3.8%; p < 0.01). CONCLUSIONS Posterior pericardial annuloplasty seems to be a safe, effective and easily performed technique and a more physiologic correction that preserves mitral annulus motion.

Chordal transposition for anterior mitral prolapse: early and long-term results.

OBJECTIVE Chordal transposition was advocated for correction of anterior mitral prolapse. We have evaluated the early and late results of this technique in different anatomical presentations. METHODS From 1986 to 1995, 185 mitral valve repairs were carried out for pure mitral regurgitation due to a degenerative disease. Eighty-nine patients had either an anterior prolapse (39) or prolapse of both leaflets (50) at initial presentation and underwent chordal transposition from the mural leaflet to the anterior leaflet. The corrective procedure was completed by polytetrafluoroethylene or pericardial posterior annuloplasty. Twenty patients presented a complex pathology and 26 had chordal elongation of mural leaflet. Annular calcifications were found in 9 patients. Seven patients required shortening of transposed chordae and two patients the additional shortening of an anterior chorda. RESULTS Operative mortality was 3.3% and follow-up was 95% complete (average 41 months). There were five postreconstruction valve replacements (two earlier and three later) for a probability of freedom from late reoperation or 3+ mitral regurgitation of 88.6 +/- 4.8% at 5 years. Of the patients 79% presented no or trivial residual MR, 17% moderate MR and 4% severe MR. The presence of a complex pathology or posterior chordal elongation did not influence the entity of postoperative residual regurgitation. On the contrary, the patients with annular calcifications had a residual regurgitation/left atrium area ratio greater than patients without annular calcification (15.8 +/- 11.5% vs. 6.1 + 9.9%; P = 0.009). CONCLUSIONS Chordal transposition is an effective and easily carried out technique for the correction of anterior mitral prolapse. The presence of a complex pathology or posterior chordal elongation do not rule out the procedure. The absence of annular calcification is important in order to obtain a satisfactory correction.

Type 2 Diabetes Mellitus Is Associated With Faster Degeneration of Bioprosthetic Valve Results From a Propensity Score–Matched Italian Multicenter Study

BACKGROUND The present study was aimed at determining the impact of type 2 diabetes mellitus (DM) on postoperative bioprosthetic structural valve degeneration. METHODS AND RESULTS Twelve Italian centers participated in the study. Patient data refer to bioprosthetic implantations performed from November 1988 to December 2009, which resulted in 6184 patients (mean age 71.3±5.4 years, 60.1% male) being enrolled. Of these patients, 1731 (27.9%) had type 2 DM. The propensity score-matching algorithm successfully matched 1113 patients with type 2 DM with the same number of no-DM patients. The postmatching standard differences were less than 0.1 for each of the covariates, and 64.2% of DM patients were matched. The early (30 days) mortality rate was 7.8% (n=87) versus 2.9% (n=33) in patients with or without type 2 DM (P<0.001), respectively. Seven-year freedom from valve deterioration was significantly lower in patients with DM (73.2% [95% confidence interval, 61.6-85.5] versus 95.4% [95% confidence interval, 83.9-100], P<0.001). In Cox regression models with robust SEs that accounted for the clustering of matched pairs, DM was the strongest predictor of structural valve degeneration (hazard ratio 2.39 [95% confidence interval 2.28-3.52]). When we allowed for interaction between type 2 DM and other key risk factors, DM remained a significant predictor beyond any potentially associated variable. CONCLUSIONS Patients with type 2 DM undergoing bioprosthetic valve implantation are at high risk of early and long-term mortality, as well as of structural valve degeneration.Background— The present study was aimed at determining the impact of type 2 diabetes mellitus (DM) on postoperative bioprosthetic structural valve degeneration. Methods and Results— Twelve Italian centers participated in the study. Patient data refer to bioprosthetic implantations performed from November 1988 to December 2009, which resulted in 6184 patients (mean age 71.3±5.4 years, 60.1% male) being enrolled. Of these patients, 1731 (27.9%) had type 2 DM. The propensity score–matching algorithm successfully matched 1113 patients with type 2 DM with the same number of no-DM patients. The postmatching standard differences were less than 0.1 for each of the covariates, and 64.2% of DM patients were matched. The early (30 days) mortality rate was 7.8% (n=87) versus 2.9% (n=33) in patients with or without type 2 DM ( P <0.001), respectively. Seven-year freedom from valve deterioration was significantly lower in patients with DM (73.2% [95% confidence interval, 61.6–85.5] versus 95.4% [95% confidence interval, 83.9–100], P <0.001). In Cox regression models with robust SEs that accounted for the clustering of matched pairs, DM was the strongest predictor of structural valve degeneration (hazard ratio 2.39 [95% confidence interval 2.28–3.52]). When we allowed for interaction between type 2 DM and other key risk factors, DM remained a significant predictor beyond any potentially associated variable. Conclusions— Patients with type 2 DM undergoing bioprosthetic valve implantation are at high risk of early and long-term mortality, as well as of structural valve degeneration. # Clinical Perspective {#article-title-46}

Fast simulations of patient-specific haemodynamics of coronary artery bypass grafts based on a POD-Galerkin method and a vascular shape parametrization

In this work a reduced-order computational framework for the study of haemodynamics in three-dimensional patient-specific configurations of coronary artery bypass grafts dealing with a wide range of scenarios is proposed. We combine several efficient algorithms to face at the same time both the geometrical complexity involved in the description of the vascular network and the huge computational cost entailed by time dependent patient-specific flow simulations. Medical imaging procedures allow to reconstruct patient-specific configurations from clinical data. A centerlines-based parametrization is proposed to efficiently handle geometrical variations. POD-Galerkin reduced-order models are employed to cut down large computational costs. This computational framework allows to characterize blood flows for different physical and geometrical variations relevant in the clinical practice, such as stenosis factors and anastomosis variations, in a rapid and reliable way. Several numerical results are discussed, highlighting the computational performance of the proposed framework, as well as its capability to carry out sensitivity analysis studies, so far out of reach. In particular, a reduced-order simulation takes only a few minutes to run, resulting in computational savings of 99 % of CPU time with respect to the full-order discretization. Moreover, the error between full-order and reduced-order solutions is also studied, and it is numerically found to be less than 1 % for reduced-order solutions obtained with just O(100) online degrees of freedom.

Computational comparison of aortic root stresses in presence of stentless and stented aortic valve bio-prostheses

We provide a computational comparison of the performance of stentless and stented aortic prostheses, in terms of aortic root displacements and internal stresses. To this aim, we consider three real patients; for each of them, we draw the two prostheses configurations, which are characterized by different mechanical properties and we also consider the native configuration. For each of these scenarios, we solve the fluid–structure interaction problem arising between blood and aortic root, through Finite Elements. In particular, the Arbitrary Lagrangian–Eulerian formulation is used for the numerical solution of the fluid-dynamic equations and a hyperelastic material model is adopted to predict the mechanical response of the aortic wall and the two prostheses. The computational results are analyzed in terms of aortic flow, internal wall stresses and aortic wall/prosthesis displacements; a quantitative comparison of the mechanical behavior of the three scenarios is reported. The numerical results highlight a good agreement between stentless and native displacements and internal wall stresses, whereas higher/non-physiological stresses are found for the stented case.

Comparison of low-dose dobutamine ventriculography with low-dose dobutamine echocardiography for predicting regional improvement in left ventricular function after coronary artery bypass grafting.

The demonstration of a contractile reserve during low-dose dobutamine echocardiography (LDDE) identifies viable myocardium and predicts recovery of left ventricular (LV) function after myocardial revascularization in patients with chronic coronary artery disease. However, a technically difficult transthoracic visualization may limit the use of LDDE, thus requiring an alternative diagnostic procedure. The present study compares LDDE with low-dose dobutamine ventriculography (LDDV) in predicting an improvement in regional LV function after surgical revascularization. We studied 18 patients with coronary artery disease and LV dysfunction who were to undergo coronary artery bypass grafting. Preoperatively, all patients were evaluated for the presence of viable myocardium using LDDE and LDDV. Follow-up echocardiography at rest and left ventriculography were performed 4 months after successful revascularization to assess recovery of LV function. The sensitivity and specificity of LDDE to identify dysfunctional segments capable of recovering function were 63% and 71%, respectively, with a diagnostic accuracy of 68%. The sensitivity, specificity, and diagnostic accuracy of LDDE improved to 81%, 72%, and 76% when patients with optimal transthoracic evaluation were selected, whereas they were 30%, 77%, and 57%, respectively, in those who underwent suboptimal evaluation. The sensitivity, specificity, and diagnostic accuracy of LDDV were 66%, 75%, and 71%, respectively, with no difference in subgroups of patients. This study demonstrates that LDDV can be considered a useful technique for identifying the presence of myocardial viability and may provide an advantage over LDDE in patients with suboptimal echocardiographic visualization.

Computational study of the risk of restenosis in coronary bypasses

Coronary artery disease, caused by the buildup of atherosclerotic plaques in the coronary vessel wall, is one of the leading causes of death in the world. For high-risk patients, coronary artery bypass graft is the preferred treatment. Despite overall excellent patency rates, bypasses may fail due to restenosis. In this context, the purpose of this work was to perform a parametric computational study of the fluid dynamics in patient-specific geometries with the aim of investigating a possible relationship between coronary stenosis degree and risk of graft failure. Firstly, we propose a strategy to prescribe realistic boundary conditions in the absence of measured data, based on an extension of Murray’s law to provide the flow division at bifurcations in case of stenotic vessels and non-Newtonian blood rheology. Then, we carry out numerical simulations in three patients affected by severe coronary stenosis and treated with a graft, in which the stenosis degree is virtually varied in order to compare the resulting fluid dynamics in terms of hemodynamic indices potentially involved in restenosis development. Our findings suggest that low degrees of coronary stenosis produce a more disturbed fluid dynamics in the graft, resulting in hemodynamic conditions that may promote a higher risk of graft failure.

Antiplatelet versus oral anticoagulant therapy as antithrombotic prophylaxis after mitral valve repair

OBJECTIVE To verify the rate of thromboembolic and hemorrhagic complications during the first 6 months after mitral valve repair and to assess whether the type of antithrombotic therapy influenced clinical outcome. METHODS Retrospective data were retrieved from 19 centers. Inclusion criteria were isolated mitral valve repair with ring implantation. Exclusion criteria were ongoing or past atrial fibrillation and any combined intraoperative surgical procedures. The study cohort consisted of 1882 patients (aged 58 ± 15 years; 36% women), and included 1517 treated with an oral anticoagulant (VKA group) and 365 with antiplatelet drugs (APLT group). Primary efficacy outcome was the incidence of arterial thromboembolic events within 6 months and primary safety outcome was the incidence of major bleeding within 6 months. Propensity matching was performed to obtain 2 comparable cohorts (858 vs 286). RESULTS No differences were detected for arterial embolic complications in matched cohort (1.6% VKA vs 2.1% APLT; P = .50). Conversely, patients in the APLT group showed lower incidence of major bleeding complications (3.9% vs 0.7%; P = .01). Six-month mortality rate was significantly higher in the VKA group (2.7% vs 0.3%; P = .02). Multivariable analysis in the matched cohort found VKA as independent predictor of major bleeding complications and mortality at 6 months. CONCLUSIONS Vitamin K antagonist therapy was not superior to antiplatelet therapy to prevent thromboembolic complications after mitral valve repair. Our data suggest that oral anticoagulation may carry a higher bleeding risk compared with antiplatelet therapy, although these results should be confirmed in an adequately powered randomized controlled trial.