Interventional vs. surgical mitral valve therapy. Which technique for which patient?

Mitral regurgitation (MR) is the most frequent valvular heart disease in developed countries. Surgical repair represents the optimal treatment for severe degenerative MR; however, surgical correction of functional MR is controversial. The Euro Heart Survey showed that up to 50 % of patients with severe MR are today denied surgical treatment. Therefore, new transcatheter techniques have been developed to treat MR with less invasive approaches. Currently, the device with the widest clinical use is the MitraClip System. In this scenario, a multidisciplinary team approach is key in providing optimal individually tailored treatment for patients with MR.

The pivotal role of echocardiography in the assessment of multivalvular heart disease.

Multivalvular heart disease (MHD) accounts for approximately 15% of the patients undergoing valve surgery in the EuroHeart Survey and for 8.6% of all valvular surgical interventions. Most clinical studies on valvular heart disease are focused on single-valve disease and very few data stress the difficulties encountered in the diagnostic assessment and clinical decision making of multiple defects, also concerning the reciprocal hemodynamic influence or the overlap of surgical indications. Many fields related to multiple valve disease are not encountered in the European Guidelines on Valvular Heart Disease (ESC) or the American College of Cardiology/American Heart Association (ACC/AHA). Increasing age and new trends of mixed population have newly aroused interest in multivalvular heart disease in the developed countries, still in need of new clinical insights. According to the high comorbidities of candidates, the appropriate diagnostic framework necessary for the correct diagnosis and best clinical outcome may still be challenging. The paper reviews multivalvular heart disease (except congenital heart disease) from aetiology and background definition to surgical outcome, with special emphasis on echocardiographic assessment and clinical interpretation.

Patient selection for MitraClip therapy impaired left ventricular systolic function.

Mitral regurgitation (MR) is a disabling disease associated with poor prognosis and high incidence of clinical events if left untreated. To reduce the invasiveness of the surgical approach, different types of transcatheter procedures are becoming available. The MitraClip procedure (Abbott Vascular Inc. Menlo Park, CA, USA) is yet the only catheter-based procedure available in clinical practice at the moment. The device has been evaluated in a number of preclinical studies, registries and in FDA approved clinical trials. (EVEREST trial, ACCESS-EU trial). Indication and timing of intervention is a crucial step in the diagnostic-therapeutic pathway of patients with mitral regurgitation. The aim of this review is to clarify the potential of MitraClip in clinical practice, particularly focusing on patient selection for this novel therapy. Patient selection and overall decision making is strongly influenced by anatomical and clinical factors. Decision-making in degenerative MR (DMR) vs. functional (FMR) can be quite different. Generally, MitraClip is effective in treating either type II or IIIb dysfunction (at the moment FMR is the main indication for MitraClip in Europe, according to the ACCESS registry data). The relative role of MitraClip and surgery in the management of patients with MR is still unclear. From the global initial experience, MitraClip therapy could be complementary to surgery in those patients at high risk for surgery who have ideal anatomical characteristics for implantation. The procedure is quite predictable in patients with favorable anatomy. In patients with suboptimal anatomy, if the risk of surgery is too high, MitraClip could be still indicated sometimes. Our preliminary experience suggests that in patients with DMR, the EVEREST anatomical criteria are strong predictors of early and mid-term success. According to it, MitraClip therapy is appropriate in those DMR patients with high surgical risk and ideal anatomy for clip implantation according to the EVEREST criteria. In FMR refractory to medical therapy and resynchronization therapy, MitraClip could be considered as first option therapy, particularly in those patients with comorbidities, or advanced age, being the operative risk of surgery above 5% in this population. In the future, novel devices, improved knowledge, more efficient imaging and transcatheter mitral prosthetic valve implantation may expand the indications to those patients currently not treated by MitraClip for anatomical unsuitability, and may improve the results both in term of early efficacy and long term durability.

Percutaneous mitral repair with the MitraClip.

Mitral regurgitation (MR) is associated with poor prognosis and high incidence of clinical events if left untreated. To reduce the invasiveness of the surgical approach, different types of trans-catheter procedures are becoming available. The MitraClip procedure (Abbott Vascular Inc. Menlo Park, CA) is yet the only available at the moment. The procedure is used to treat high risk surgical candidates with either functional or degenerative MR. Recent trials have shown that the procedure is safer than surgery, although less effective. Efficacy of the procedure depends on several factors, including patient selection, anatomy of the valve and the experience of the operators. However, when treating high risk patients a suboptimal repair obtained with low risk can be a acceptable outcome. In the future, novel devices, improved knowledge, more efficient imaging and transcatheter mitral prosthetic valve implantation may expand the indications to those patients currently not treated by MitraClip for anatomical unsuitability, as well as may improve the results both in term of early efficacy and long term durability.

Determinants of the degree of functional aortic regurgitation in patients with anatomically normal aortic valve and ascending thoracic aorta aneurysm. Transoesophageal Doppler echocardiography study.

OBJECTIVES: To identify functional aortic regurgitation (FAR) determinants in patients with ascending thoracic aortic aneurysm (ATAA) and surgically confirmed normal aortic valve anatomy. DESIGN: Case-control study. SETTING: Non-invasive Cardiology and Cardiac Surgery Department. PATIENTS: Eighty-nine patients with ATAA and varying degrees of FAR undergoing surgery, 40 age-matched patients with ATAA without aortic regurgitation and 20 normal control subjects. INTERVENTIONS: Doppler and two-dimensional transoesophageal echocardiography. MAIN OUTCOME MEASURES: Vena contracta (VC) of aortic regurgitant jet, diastolic tented area and coaptation height (CH) of aortic valve leaflets, aortic dimension indexes-Valsalva sinus, sinotubular junction (STJ), tubular tract, annulus (A), STJ/A ratio. RESULTS: When VC was used, a wide range of FAR was seen (mean (SD) 5.59 (2.59) mm, ranging from 2 to 13 mm). Of the variables tested, the most strongly associated with FAR severity in multivariate analysis was diastolic leaflet tenting, measured as CH (R(2) = 0.69) (sensitivity 98%, specificity 95% using a cut-off value of CH > or =1.1 cm). In turn, the diastolic leaflet tenting was strongly identified by the STJ/A ratio (sensitivity 87%, specificity 71% using a cut-off value of STJ/A >1.66). CONCLUSION: The diastolic tenting of aortic leaflets is strongly related to FAR severity in patients with ATAA. The mismatch of STJ/A is significantly associated with diastolic leaflet tenting and its correlated valve regurgitation, independently of the actual ATAA dimension. These findings provide new insight into the mechanism of FAR arising from ATAA.

Revascularization of hibernating myocardium: rate of metabolic and functional recovery and occurrence of oxidative stress.

BACKGROUND: Left ventricular (LV) dysfunction due to coronary artery disease (CAD) may improve after revascularization in patients with hibernating myocardium (HM). METHODS AND RESULTS: We compared the rate of metabolic (arterial-great cardiac vein differences of lactate, glucose and pyruvate) and functional (intra-operative transesophageal and epicardial echocardiography) recovery and occurrence of oxidative stress (myocardial release of oxidized glutathione (GSSG)) early after surgical revascularization, in patients with CAD, LV dysfunction and HM (n=16) vs those with preserved LV function (n=15). By comparing the two groups, we observed that, after de-clamping, in patients with HM (a) the kinetic of lactate production was converted to extraction (P<0.01 at 1, 5, 10 and 20 min after revascularization), (b) myocardial extraction of pyruvate increased (P<0.01 during the first 5 min after revascularization), (c) GSSG release was less and of shorter duration (P<0.01 at all times), (d) segmental wall motion score improved from 2.4+/-0.3 to 1.7+/-0.5 (P<0.01) as did the thickening of the akinetic territories corresponding to the antero-distal septum and to the distal anterior wall regions (to 36+/-23%, and to 36+/-13%, respectively). There was a correlation between the rate of recovery of metabolic and functional indices. CONCLUSIONS: The contractile and metabolic recovery of HM is more rapid than that of non-HM, and it is not accompanied by oxidative stress.

The double-orifice technique in mitral valve repair: a simple solution for complex problems.

OBJECTIVE: The aim of this study is to report our results with the central double-orifice technique used for the treatment of complex mitral valve lesions. METHODS: The central double-orifice repair has been used in 260 patients (mean age, 56 +/- 14.3 years) over a period of 7 years. The mechanism responsible for mitral regurgitation was prolapse of both leaflets in 148 patients, prolapse of the anterior leaflet in 68, prolapse of the posterior leaflet with annular calcification or other unfavorable features in 31, and lack of leaflet coaptation for restricted motion or erosion of the free edge in 13. Degenerative disease was the cause of mitral regurgitation in 80.8% of the patients, rheumatic disease was the cause in 9.6%, endocarditis was the cause in 6.1%, and ischemic disease was the cause in 2.3%. RESULTS: Hospital mortality was 0.7%, and the overall survival at 5 years was 94.4% +/- 2.59%. Thirteen patients required a reoperation (2 early postoperatively and 11 late during the follow-up), for an overall freedom from reoperation of 90.0% +/- 3.37% at 5 years. Freedom from reoperation was lower in patients with rheumatic valve disease and in patients who did not undergo an annuloplasty procedure. CONCLUSIONS: The effectiveness and durability of the central double-orifice technique were assessed in this study. This type of repair can be a useful addition to the surgical armamentarium in mitral valve reconstruction.

Long-term results of coronary artery bypass grafting procedure in the presence of left ventricular dysfunction and hibernating myocardium.

OBJECTIVE: Long-term left ventricular (LV) performance and patient outcome after coronary artery bypass grafting (CABG) procedure in the presence of depressed LV function and hibernating myocardium (HM) have been poorly determined. Therefore, we prospectively evaluated patients undergoing CABG with severe LV dysfunction and HM to elucidate postoperative prognosis. METHODS: We enrolled 120 consecutive patients undergoing CABG with severe LV dysfunction and HM as assessed by dobutamine echocardiography and by rest-redistribution radionuclide (Thallium-201) study. Mean patient age was 60+/-9 years (range 31-77 years). Mean preoperative LVEF was 28%+/-9 (range 10-40%). All patients underwent echocardiographic study to assess LV recovery of function intraoperatively, prior to hospital discharge, at 3 months, at 1 year, and yearly during the follow-up. Univariate and multivariate analysis were performed to to evaluate predictors of postoperative survival. RESULTS: There were 2 hospital (1.6%) and 15 late (12.5%) deaths, mainly for heart failure, leading to an actuarial survival of 80+/-6% and 60+/-9% at 5 and 8 years, respectively. LVEF significantly improved perioperatively (from 28+/-9% to 40+/-2%, P<0.01). Increase in LVEF, however, was gradually offset over the time (EF of 33+/-9%, 32+/-8%, and 30+/-9% at 3 months, and 12 months, and 8 years after surgery, respectively). Furthermore, patients who experienced limited LV functional recovery perioperatively had a more remarkable decline of LVEF thereafter, and suffered from recurrence of heart failure symptoms (freedom from heart failure 82+/-5% and 60+/-8% at 4 and 8 years respectively). Advanced preoperative NYHA Class, and age were independent risks factors for reduced postoperative survival. Preoperative angina and use of arterial conduits apparently did not influence patient morbidity and mortality at long term. CONCLUSION: CABG procedure in the presence of HM enhances LV recovery of function and has a favourable prognosis. Functional benefit of the left ventricle, however, appears to be time-limited, despite remarkable improvement in patient functional capacity. Advanced preoperative heart failure, minimal perioperative improvement of LVEF, and age account for a poor long-term prognosis.

Gated blood pool tomography for the evaluation of global and regional left ventricular function in comparison to planar techniques and echocardiography.

BACKGROUND: Multigated radionuclide ventriculography (MUGA) is a simple and reliable tool for the assessment of global systolic and diastolic function and in several studies it is still considered a standard for the assessment of left ventricular ejection fraction. However the evaluation of regional wall motion by MUGA is critical due to two-dimensional imaging and its clinical use is progressively declining in favor of echocardiography. Tomographic MUGA (T-MUGA) is not widely adopted in clinical practice. The aim of this study was to compare T-MUGA to planar MUGA (P-MUGA) for the assessment of global ejection fraction and to transthoracic echocardiography for the evaluation of regional wall motion. METHODS: A 16-segment model was adopted for the comparison with echo regional wall motion. For each one of the 16 segments the normal range of T-MUGA ejection fraction was quantified and a normal data file was defined; the average value -2.5 SD was used as the lower threshold to identify abnormal segments. In addition, amplitude images from Fourier analysis were quantified and considered abnormal according to three different thresholds (25, 50 and 75% of the maximum). RESULTS: In a study group of 33 consecutive patients the ejection fraction values of T-MUGA highly correlated with those of P-MUGA (r = 0.93). The regional ejection fraction (according to the normal database) and the amplitude analysis (50% threshold) allowed for the correct identification of 203/226 and 167/226 asynergic segments by echocardiography, and of 269/302 and 244/302 normal segments, respectively. Therefore sensitivity, specificity and overall accuracy to detect regional wall motion abnormalities were 90, 89, 89% and 74, 81, 79% for regional ejection fraction and amplitude analysis, respectively. CONCLUSIONS: T-MUGA is a reliable tool for regional wall motion evaluation, well correlated with echocardiography, less subjective and able to provide quantitative data.

[Epicardial ablation of atrial fibrillation during heart valve surgery]. / Ablazione epicardica della fibrillazione atriale durante chirurgia valvolare.

BACKGROUND: We report the results of an intraoperative ablation procedure for combined treatment of atrial fibrillation (AF) in patients affected by heart valve disease. METHODS: From February 1998 to June 2000, 80 patients scheduled for heart valve operations underwent combined surgical treatment of AF. Seventy-eight patients had mitral valve disease and 2 had aortic regurgitation; 74 patients were affected by chronic AF (mean 50 +/- 74 months, range 6-480 months) and 6 had paroxysmal AF. A left atrial set of radiofrequency ablations (mainly epicardial) was performed in all patients. RESULTS: Thirty-five patients underwent conservative mitral valve surgery, 43 had mitral valve replacement and 2 had aortic valve replacement. The combination of the ablation procedure did not lead to a substantial prolongation of cardiopulmonary and aortic cross clamp time and did not increase perioperative morbidity. No procedure-related complications were recorded. Operative mortality was favorably comparable with that of valvular surgery alone (2.5%). Mean hospital stay was 6.8 +/- 4.4 days. At follow-up (16.2 +/- 9.2 months, range 3-28 months), 61 patients (78.2%) were in stable sinus rhythm; all of them recovered left and right atrial contractility as assessed by Doppler echocardiography. CONCLUSIONS: The combined treatment of AF with a radiofrequency ablation surgical technique is effective in restoring stable sinus rhythm and atrial contractility. The procedure is low risk thereby allowing a prompt clinical recovery after operation. It should therefore be considered in all patients with AF undergoing open-heart surgery.

[Evaluation of hibernating myocardium in patients with heart insufficiency]. / La valutazione del miocardio ibernato nei pazienti con insufficienza cardiaca.

Myocardial dysfunction due to chronic hypoperfusion (so-called hibernating myocardium) is potentially reversible if the normal coronary flow is restored. Stress echocardiography (dobutamine, post-extrasystolic potentiation) may elicit contractile reserve of the hibernating myocardium and predict accurately its functional recovery after coronary revascularization. Thus, the identification of dysfunctioning but viable myocardium may be crucial to select patients with ischemic congestive heart failure who might benefit from coronary revascularization.

Sensitivity, specificity, and predictive accuracies of non-invasive tests, singly and in combination, for diagnosis of hibernating myocardium.

OBJECTIVE: To determine the best test(s) for predicting functional recovery of hibernating myocardium after reperfusion. METHODS: A prospective study to compare echocardiographic left ventricular diastolic wall thickness (> or =5 mm), low-dose dobutamine echocardiography and rest-redistribution thallium-201 scintigraphy, alone and in combination, for predicting recovery of left ventricular akinesis after surgical revascularization. RESULTS: Twenty-eight consecutive patients aged 58+/-9 years were studied. Of the 448 left ventricular segments, 263 were akinetic at rest; 230/263 (87%) had wall thickness > or =5 mm, 135 (51%) had a positive response and 175 (66.5%) were graded viable on thallium. Of akinetic segments 61% improved after surgery. Left ventricular score decreased from 2.3+/-0.4 to 1.8+/-0.4 (P<0.01) and ejection fraction increased from 27+/-10 to 37+/-14% (P<0.01). For predicting results at 1 year, diastolic wall thickness had a sensitivity and a predictive accuracy of a negative test of 100% but a specificity of 28% and predictive accuracy of a positive test of 61%. The addition of dobutamine echocardiography or thallium-201 improved the predictive accuracy of a positive test to 76% and 69%, respectively; the addition of both tests was not of greater benefit than that of a single test. CONCLUSIONS: Diastolic wall thickness <5 mm on echocardiography was the best simple and single predictor of non-recovery of left ventricular dysfunction. The addition of dobutamine echocardiography or thallium-201, but not both, was the best solution for predicting recovery of left ventricular dysfunction. In times of limited resources, these findings are important from a clinical point of view.

Mitral valve repair for isolated prolapse of the anterior leaflet: an 11-year follow-up.

OBJECTIVE: Mitral valve insufficiency (MVI) because of involvement of the anterior mitral leaflet may pose additional risks for late outcome after mitral valve repair, because of more complex techniques. We retrospectively reviewed our experience in patients operated on for isolated anterior mitral leaflet prolapse approached by various techniques. METHODS: Between 1986 and 1997, 616 patients underwent mitral valve repair at our Institution. Isolated pathology of the anterior mitral leaflet was the cause of MVI in 84 patients (13.6%). Age ranged from 23 to 74 years (mean 50 +/- 14). Etiology of MVI was predominantly degenerative (57 patients, 67.8%), and the mechanism of the regurgitation was mainly due to a chordal rupture (58 patients, 69%). Annular dilatation was present in 75 patients (89.5%). A variety of surgical techniques were applied including chordal shortening (five patients, 5.9%), chordal transposition (three patients, 3.5%), artificial chordae (11 patients, 13%). Since 1992, however, the majority of procedures was performed using the 'edge to edge' technique (52 patients, 51.9%). Annular dilatation was treated mainly by means of a prosthetic ring (46 patients, 61.3%) whereas 18 patients (24%) underwent posterior annuloplasty using gluteraldehyde-treated native pericardium. RESULTS: Follow-up ranged from 3 to 122 months (mean 46 +/- 24 months). There were three hospital deaths (3.5%) and five late deaths (5.9%) for a Kaplan-Meier estimated survival of 87.6% at 8 years. Three patients underwent early reoperation within 30 days (3.5%), and six patients underwent late reoperation (7.1%), for a cumulative freedom from reoperation of 85.4% at 8 years. Seventy-four percent of the survivors (50 patients) are still in New York Heart Association Class I, and 92% of survivors (62 patients) have no or trivial (1+) residual mitral regurgitation at echocardiographic follow-up. CONCLUSION: In spite of the greater complexity, conservative surgery to correct anterior mitral valve prolapse pertains high success rate of long term. Recent technical modifications ('edge-to-edge' technique) may allow more expeditious and reproducible procedures with expected favorable influence of mitral valve repair applicability.

Different outcomes of the reperfused myocardium: insights into the comments of stunning and hibernation.

There are several potential outcomes of myocardial ischaemia. When ischaemia is severe and prolonged, irreversible damage occurs and there is no recovery of contractile function. Interventions aimed at reducing mechanical activity and oxygen demand either before ischaemia or during reperfusion have been shown to delay the onset of ischaemic damage and to improve recovery during reperfusion. When myocardial ischaemia is less severe but still prolonged, myocytes may remain viable but exhibit depressed contractile function. Under these conditions, reperfusion restores complete contractile performance. This type of ischaemia leading to a reversible, chronic left ventricular dysfunction has been termed 'hibernating myocardium'. It is important clinically recognize hibernation as reperfusion of hibernating myocardium by angioplasty or heart surgery restores contraction and this correlates with long term survival. A third possible outcome after a short period of myocardial ischaemia is a transient post-ischaemic ventricular dysfunction, a situation termed 'stunned myocardium'.

Evaluation of mean right atrial pressure by two-dimensional and Doppler echocardiography in patients with cardiac disease.

BACKGROUND: Several approaches have been used for noninvasive estimation of right atrial pressure (RAP), but, no currently available method has gained any definite validation. The purpose of this study was to evaluate the accuracy of two-dimensional and Doppler echocardiography in estimating mean RAP in patients with cardiac disease. METHODS: We examined the relation of mean RAP to right atrial size and function, size and respiratory changes of inferior vena cava and Doppler parameters of tricuspid and hepatic vein flow in 114 consecutive patients (77 men, 37 women; mean age 57 +/- 12 years) with various cardiac diseases undergoing cardiac catheterization. Echocardiographic studies were performed within 24 hours before catheterization (mean interval 6 +/- 3 hours). Patients were assigned to 3 groups according to the values of mean RAP (group 1, < or = 8 mmHg; group 2, between 9 and 12 mmHg; group 3, > 12 mmHg). RESULTS: Mean RAP ranged from 3 to 20 mmHg (mean 9.1 +/- 4.3 mmHg). It correlated most strongly with the collapsibility index of inferior vena cava (IVCCI) (r = -0.76), minimal inspiratory diameter of inferior vena cava (r = 0.72) and deceleration time of early tricuspid flow (DT) (r = -0.61). Discriminant analysis demonstrated that IVCCI and DT were major determinants of mean RAP with 81.6% of cases correctly assigned to study groups: 96% of patients of group 1 and 87% of patients of group 3 were identified, whereas the accuracy in identifying the patients of group 2 was lower (46%). An IVCCI > 45% was the best cutoff point in predicting a mean RAP < or = 8 mmHg; an IVCCI < 35% and a DT < 150 msec were the best cutoff points in predicting a mean RAP > or = 15 mmHg. The best multivariate equation predicting mean RAP was: mean RAP = 23.3 - 0.2 IVCCI -0.026 DT (r = 0.80, R2 = 0.64). This equation was 81% sensitive and 84% specific in detecting a mean RAP < or = 8 mmHg and 74% sensitive and 97% specific in detecting a mean RAP > 12 mmHg. CONCLUSIONS: Mean RAP can be estimated noninvasively by two-dimensional and Doppler echocardiography. The combined analysis of IVCCI and DT provides an accurate prediction on mean RAP < or = 8 mmHg and > 12 mmHg, whereas the prediction of intermediate values is less accurate.

The edge-to-edge technique: a simplified method to correct mitral insufficiency.

OBJECTIVE: Repair of mitral regurgitation (MR) is more demanding in case of prolapse of the anterior leaflet, posterior leaflet with calcified annulus, or prolapse of both leaflets. We evaluated a repair which consists of anchoring the free edge of the prolapsing leaflet to the corresponding free edge of the facing leaflet: the 'edge-to-edge' (E-to-E) technique. The correction results in a double orifice valve when the prolapse is in the middle portion of the leaflet and in a smaller valve orifice when the prolapse is close to a commissure. METHODS: Out of 432 patients with MR submitted to valve repair between January 1991 and September 1997, 121 (mean age 56 +/- 15.8 years) underwent E-to-E correction. The most prevalent etiology was degenerative disease (82 patients, 68%). The mechanism of MR was anterior leaflet prolapse (61 patients), posterior leaflet prolapse (24 patients), prolapse of both leaflets (28 patients) and other complex mechanisms (8 patients). In 72 patients, a double orifice was created, the paracommissural repair was done in 49 patients. RESULTS: Hospital mortality was 1.6%. Overall survival was 92 +/- 3.1% at 6 years with 95 +/- 4.8% freedom from reoperation. Mortality was unrelated to the type of repair. Mitral stenosis was never observed after the correction. At the follow-up (mean 2.2 +/- 1.5 years), all patients but 15 are class I or II. Symptoms at the follow-up are not related to residual MR. CONCLUSIONS: Midterm results of this alternative repair technique are promising, considering the high prevalence of complex anatomical lesions. The technique is simple, easily reproducible and rapidly feasible also when mitral exposure is suboptimal.

"Double-orifice" technique to repair extensive mitral valve excision following acute endocarditis.

The use of conservative surgical techniques to treat mitral valve regurgitation secondary to acute endocarditis is controversial. Reconstruction of the anterior leaflet may represent an additional challenge in such a setting. We report a case of mitral valve repair where extensive excision of the anterior leaflet and related chordae tendinea was necessary because of large vegetation secondary to acute endocarditis. The "double-orifice" technique was performed and allowed the salvage of the native valve. There was no recurrent infection at 6 months from surgery, with optimal hemodynamic results.