Restrictive Mitral Annuloplasty With or Without Papillary Muscle Approximation for Functional Mitral Regurgitation

BACKGROUND AND AIM OF THE STUDY

The impact of adding papillary muscle approximation (PMA) to restrictive mitral annuloplasty (RMA) on postoperative left ventricular (LV) function is unknown. Changes in LV function parameters and clinical outcome were evaluated following RMA with and without PMA in patients with clinically relevant functional mitral regurgitation (FMR).

METHODS

A total of 176 patients with advanced cardiomyopathy underwent RMA either with (n = 59) or without (n = 117) PMA. Propensity score analysis was used to adjust for group differences in several baseline characteristics, such as age, gender and LV ejection fraction (LVEF) (C-statistic = 0.80, goodness-of-fit value = 0.58).

RESULTS

Serial echocardiography in 30 propensity score-matched pairs demonstrated decreases in LV end-systolic dimension (RMA alone: 57 ± 9 mm at baseline versus 54 ±11 mm at one month versus 56 ± 13 mm at latest examination; RMA + PMA: 56 ± 8 mm versus 53 ± 9 mm versus 48 ± 11 mm, respectively) and improvement in LVEF (RMA alone: 28 ± 8% versus 28 ± 11% versus 29 ± 10%; RMA + PMA: 30 ± 8% versus 30 ± 9% versus 36 ± 13%, respectively) in both groups. Greater degrees of changes in value were noted for patients receiving RMA + PMA (group effect p <0.05 for both). The two-year survival of both groups was similar (73 ± 8% versus 77 ± 23%, p = 0.7), but the RMA + PMA group showed a trend towards a greater freedom from composite events, defined as mortality and/or unscheduled heart failure re-admission (48 ± 9% versus 63 ± 9%, p = 0.1).

CONCLUSIONS

RMA + PMA induced greater long-term effects on unloading of the left ventricle and improvements in LV systolic function than did RMA alone. PMA may be a useful adjunct repair in combination with RMA, although its clinical benefits remain to be determined.

Predictors and Clinical Impact of Functional Mitral Stenosis Induced by Restrictive Annuloplasty for Ischemic and Functional Mitral Regurgitation

BACKGROUND

There are few reports of the determinants of "functional" mitral stenosis in terms of a residual mitral valve (MV) pressure gradient >5 mmHg following restrictive mitral annuloplasty (RMA) or the effect on long-term outcome in patients with functional mitral regurgitation (MR).Methods and Results:Serial cardiac catheterization and echocardiographic studies were performed in 55 patients with functional MR who underwent RMA using a 24/26-mm semi-rigid complete ring. The mean postoperative (1 month) catheter-measured MV gradient was 3.4±1.6 mmHg, which was independently associated with corresponding cardiac output [standardized partial regression coefficient (SPRC)=0.59] and indexed effective orifice area (SPRC=-0.25). Body surface area (BSA) had the greatest contribution to MV gradient (SPRC=0.38), followed by use of a 24-mm ring (SPRC=0.33) and hemodialysis (SPRC=0.26). Receiver-operating characteristic curve analysis demonstrated an optimal BSA cutoff value of 1.86 m²to predict post-MV stenosis (21% for <1.86 m²vs. 86% for ≥1.86 m², P=0.002). During follow-up (75±32 months), freedom from adverse events did not differ between patients with (n=16) and without (n=39) an MV gradient ≥5 mmHg (log-rank P=0.24).

CONCLUSIONS

Post-RMA MV gradient was determined not only by the degree of annular reduction but also by patients' hemodynamic factors (e.g., cardiac output). Implantation of a 24/26-mm annuloplasty ring for patients with BSA ≥1.86 m²indicated a high likelihood of post-MV stenosis. However, mild MV stenosis did not adversely affect late outcome after RMA.

Analysis of the sternum for sternal closure with bioabsorbable sternal pins

PURPOSE

Poly-L-lactide sternal pins have been reported to be beneficial for sternal closure. However, we sometimes experience a small sternum, and the size characteristics of the sternum have not been fully investigated. We analyzed size features of the sternum to determine the optimal size of sternal pin for sternal closure.

METHODS

Chest computed tomography scans were preoperatively obtained in 144 patients undergoing major cardiovascular surgery. We reviewed all scans at the level of the sternum, and measured the width of the bone marrow of the sternum on each computed tomography slice.

RESULTS

The mean values of bone marrow width of the sternal manubrium and body of male patients were significantly higher than those of females (manubrium: 38.6 ± 3.9 mm in males, 34.5 ± 3.3 mm in females, p < 0.0001; body: 23.4 ± 3.7 mm in males, 20.8 ± 2.8 mm in females, p < 0.0001). There was no correlation between the bone marrow width of the sternal body and body surface area in either males or females (males: r = 0.08, p = 0.45, females: r = 0.08, p = 0.58).

CONCLUSION

To select the appropriate size of sternal pin, preoperative measurement of the bone marrow width of the sternum is recommended because it cannot be predicted from body size.

Total arch replacement with long elephant trunk anastomosed at the base of the innominate artery: a single-centre longitudinal experience

OBJECTIVE

Total arch replacement, with a long elephant trunk (ET) anastomosed at the base of the innominate artery using an undersized graft, is performed for a variety of arch aneurysms. We investigated the long-term clinical outcomes of this procedure, as well as its long-term effectiveness for preventing retrograde flow into the aneurysm and further dilation of the descending aorta.

METHODS

We treated 127 consecutive patients with an arch aneurysm, who were divided into two groups according to the diameter of the descending aorta at the Th6-Th8 thoracic vertebral level: 35 mm or less (Single-ET, n = 94) and >35 mm (Staged-ET, n = 33). The graft diameter was undersized by 10-20% of the distal aortic diameter. ET length was determined by preoperative computed tomography (CT) to locate the distal end at Th6-Th8. Thrombosis around the ET and the descending aorta diameter around the distal end of the ET were evaluated using CT.

RESULTS

Two patients (1.6%) died within 30 days, while seven (5.5%) died in the hospital, three (2.4%) had a new stroke, three (2.4%) had permanent paraplegia and one (0.8%) had paraparesis. CT demonstrated complete thrombosis of the perigraft space around the ET in 81 patients (86%) in the Single-ET group and 11 (33%) in the Staged-ET group within 1 month after surgery, but not in the remaining 35 patients. Twenty-seven of the 35 patients without complete thrombosis underwent a subsequent second-stage operation. In those, the descending aorta showed no further dilation around the distal end of the ET, while new-onset perigraft perfusion occurred in two patients in the Single-ET group at 14 and 126 months, respectively. Overall survival was 89, 86, 78 and 74% at 1, 3, 5 and 7 years, respectively.

CONCLUSIONS

Our operative strategy for extensive thoracic aortic aneurysms using a long ET technique yielded satisfactory short- and long-term outcomes.

Unusual presentation of multiple recurrent cardiac sarcomas as acute acalculous cholecystitis caused by rapid expansion into the right cardiac chamber: report of a case

Sarcomas are rare malignant cardiac tumors and their prognosis is extremely poor, with a high recurrence rate despite extensive initial surgical resection. The development of therapeutic alternatives looks bleak for recurrent sarcomas, however, and complete surgical resection is crucial for any hope of survival even for the recurrent patients. We herein report the case of a 38-year-old male patient with multiple recurrent cardiac sarcomas causing acute acalculous cholecystitis 20 months after the resection of the primary tumor.

Does stringent restrictive annuloplasty for functional mitral regurgitation cause functional mitral stenosis and pulmonary hypertension?

BACKGROUND

It remains controversial whether restrictive mitral annuloplasty (RMA) for functional mitral regurgitation (MR) can induce functional mitral stenosis (MS) that may cause postoperative residual pulmonary hypertension (PH).

METHODS AND RESULTS

One hundred eight patients with left ventricular (LV) dysfunction and severe MR underwent RMA with stringent downsizing of the mitral annulus. Systolic pulmonary artery pressure (PAP) and mitral valve performance variables were determined by Doppler echocardiography prospectively and 1 month after RMA. Fifty-eight patients underwent postoperative hemodynamic measurements. Postoperative echocardiography showed a mean pressure half-time of 92 ± 14 ms, a transmitral mean gradient of 2.9 ± 1.1 mm Hg, and a mitral valve effective orifice area of 2.4 ± 0.4 cm(2), consistent with functional MS. Doppler-derived systolic PAP was 32 ± 8 mm Hg, which correlated weakly with the transmitral mean gradient (ρ=0.23, P=0.02). Postoperative cardiac catheterization also showed significant improvements in LV volume and systolic function, pulmonary capillary wedge pressure, cardiac index, and systolic PAP; the latter was associated with LV end-diastolic pressure [standardized partial regression coefficient (SPRC)=0.51], pulmonary vascular resistance (SPRC=0.47), cardiac index (SPRC=0.37), and transmitral pressure gradient (SPRC=0.20). In a multivariate Cox proportional hazard model, postoperative PH (systolic PAP >40 mm Hg), but not mitral valve performance variables, was strongly associated with adverse cardiac events.

CONCLUSIONS

RMA for functional MR resulted in varying degrees of functional MS. However, our data were more consistent with the residual PH being caused by LV dysfunction and pulmonary vascular disease than by the functional MS. The residual PH, not functional MS, was the major predictor of post-RMA adverse cardiac events.

A case of successful valve repair for aortic insufficiency associated with discrete subaortic stenosis

Discrete subaortic stenosis (DSS) is an uncommon form of left ventricular outflow tract obstruction especially in adulthood. Moreover, aortic regurgitation (AR), which is a common sequence of DSS, requiring surgical correction is extremely rare. We report the case of a 33-year old man who had severe DSS accompanied with moderate aortic insufficiency. He underwent successful surgery including relief of DSS and aortic valve repair. Although careful follow-up is mandatory for recurrent AR and DSS, our approach was thought to be feasible for a young adult patient with DSS complicated with AR.

Successful bridge to recovery in a patient surviving fatal device-related complications after implantation of a Toyobo left ventricular assist system

Emergent left ventricular assist system (LVAS) removal due to device complication is associated with high morbidity and mortality. This report describes a case of a 51-year-old man with dilated cardiomyopathy who successfully underwent emergent LVAS removal after a device-related complication. Although the patient's left ventricular function was still compromised, LVAS removal was indicated secondary to cerebral hemorrhage. Fortunately, the patient had an uneventful course over the ensuing 8 months and maintained good quality of life.

Advanced left-atrial fibrosis is associated with unsuccessful maze operation for valvular atrial fibrillation

OBJECTIVE

Atrial dilatation and fibrosis are considered to be important factors in the occurrence and maintenance of atrial fibrillation (AF). However, the relationship between those structural remodeling and postoperative sinus conversions after a maze operation has been rarely studied. The purpose of this study was to determine whether pathological evaluation of atrial tissues was useful for predicting an unsuccessful maze operation in patients with valvular AF.

METHODS

Between March 2006 and June 2007, left-atrial tissues in the posterior wall and right-atrial appendage were obtained from 47 consecutive patients (24 patients with chronic AF, and 23 with sinus rhythm) undergoing mitral valve surgery (MVS). A concomitant maze operation was performed for all patients with chronic AF. Atrial cell diameters were measured using hematoxylin and eosin staining, and quantitative assessment of atrial fibrosis was performed with Masson trichrome staining using an image analyzer (Image Processor for Analytical Pathology, Sumika Technoservice Co., Hyogo, Japan).

RESULTS

Successful MVS was performed for all patients and there were no complications associated with tissue sampling. Patients with chronic AF had more advanced histological features in both atria as compared with those with sinus rhythm. Sixteen of 24 patients, who underwent a maze operation, had successfully restored sinus rhythm (successful maze group), while that in the remaining eight was not restored (unsuccessful maze group). Patients in the unsuccessful maze group had a larger left-atrial dimension and cardiothoracic ratio as compared with those in the successful group, whereas the duration of AF was not significantly different. Patients in the unsuccessful maze group also had greater hypertrophy of cardiomyocytes and more extensive intercellular fibrosis in the left atrium, while there were no differences for right-atrial pathological features between the groups. Multivariate logistic analysis confirmed that a larger amount of left-atrial fibrosis (>15%) was significantly associated with an unsuccessful maze operation.

CONCLUSIONS

The present results suggested that advanced fibrosis in the left atrium, but not in the right atrium, might be significantly associated with an unsuccessful maze operation in patients with valvular AF.

Serious acute coronary thrombosis associated with heparin-induced thrombocytopenia in off-pump coronary artery bypass grafting

A 72-year-old female underwent off-pump coronary bypass grafting one month after heparin exposure. Immediately after protamine administration, she developed hypotension due to acute graft failure. Grafting to left anterior descending branch was revised under intra-aortic balloon pump insertion and she was transferred to intensive care unit under stable hemodynamic condition. However, she gradually developed low cardiac output syndrome and echocardiography showed new onset of myocardial infarction. Coronary angiography on the first postoperative day revealed diffuse serious coronary thrombosis involving all grafts and grafted native coronary arteries. Emergent percutaneous coronary intervention (PCI) was performed for native vessels. Laboratory examination revealed severe progressive thrombocytopenia and she was clinically diagnosed as heparin-induced thrombocytopenia (HIT). After cessation of all heparins and alternative anticoagulation with argatroban, thrombocytopenia was improved and some of occluded grafts were recanalized. She was discharged on the 51st postoperative day. Acute graft thrombosis, especially caused by HIT, is a serious complication, which sometimes results in mortality. This is a successful case treated by PCI followed by an alternative anticoagulation.

Percutaneous cardiopulmonary support after acute myocardial infarction at the left main trunk

BACKGROUND

Percutaneous cardiopulmonary support (PCPS) has recently become an accepted modality for the treatment of cardiogenic shock after acute myocardial infarction (AMI). However, the clinical outcomes of patients with AMI at the left main trunk (LMT) undergoing PCPS remain unclear.

PATIENTS AND METHODS

From January 2000 to September 2007, we experienced 16 cases of AMI at the LMT requiring emergent PCPS. The average age ranged from 56 to 74 (mean 68.8), and 13 were male. All cases underwent percutaneous coronary intervention (PCI). The maximum creatine kinase leakage ranged from 6,069 to 22,580 IU/l (mean; 12,880 IU/l). The time to revascularization ranged from 30 min to 1,138 min (mean 229 min). An intra-aortic balloon pumping (IABP) was inserted in all patients.

RESULTS

Among our 16 patients, 10 (62.5%) could be successfully weaned off PCPS, and 6 (37.5%) could be weaned off both PCPS and IABP and discharged. Three patients underwent left ventricular assist system (LVAS) implantation. Two of them, without preoperative severe systemic complications, survived more than 100 days after implantation, whereas the third died perioperatively because of a systemic complication from the preoperative period. Eight patients died of low output syndrome or brain death. Cardiac function did not recover in patients in whom the time to revascularization was more than 4 hours and PCPS support duration more than 3 days.

CONCLUSIONS

The clinical outcomes of patients with LMT disease requiring PCPS is not satisfactory. In order to improve clinical outcomes of these patients, a strategy involving a timely insertion of LVAS before the onset of complications might be necessary.

Left ventricular myocardial remodeling and contractile state in chronic aortic regurgitation

BACKGROUND

In chronic aortic regurgitation, eccentric hypertrophy, with combined concentric hypertrophy of the left ventricle, is an important adaptive response to volume overload, which in itself is a compensatory mechanism for permitting the ventricle to normalize its afterload and to maintain normal ejection performance (physiologic hypertrophy). However, progressive dilatation of the left ventricle leads to depressed left ventricular (LV) contractility and myocardial structural changes, including cellular hypertrophy and interstitial fibrosis (pathological hypertrophy).

HYPOTHESIS

The study was undertaken to determine the relationship between left ventricular myocardial structure and contractile function in 14 patients with chronic aortic regurgitation by cardiac catheterization and endomyocardial biopsies.

METHODS

Myocardial cell diameter and percent interstitial fibrosis were obtained from biopsy samples. Contractile function was evaluated from the ratio of end-systolic wall stress to end-systolic volume index (ESS/ESVI) and the ejection fraction-end-systolic stress (EF-ESS) relationship, which was obtained from 30 normal control subjects.

RESULTS

Myocardial cell diameter correlated significantly with the ESVI (r = 0.72, p < 0.005), ejection fraction (r = -0.58, p < 0.05), and ESS/ESVI (r = -0.58, p < 0.05). The percent interstitial fibrosis also correlated inversely with ESS/ESVI (r = -0.71, p < 0.005). Compared with very few patients with an ESVI < 70 ml/m2, the majority of patients with ESVI > or = 70 ml/m2 had a cell diameter of > or = 30 microns and a percent interstitial fibrosis of > or = 10%. The nine patients who had depressed contractile function, as assessed from the EF-ESS relationship, had a higher percent interstitial fibrosis (p < 0.05) than five patients showing a normal EF-ESS relationship, despite the fact that there was no significant difference in myocardial cell diameter between them. Thus, advanced cellular hypertrophy and excessive interstitial fibrosis were significantly and independently associated with myocardial contractile dysfunction and appeared to be responsible for ventricular remodeling.

CONCLUSION

Our findings suggest that in many patients with aortic regurgitation, eccentric hypertrophy changes its nature from physiologic to nonphysiologic during the earlier stages in the course of the disease rather than during the stage described previously.

Successful surgical management for severe mitral regurgitation unmasked after pericardiectomy for chronic constrictive pericarditis

A 78-year-old cachectic woman who previously had repair of atrial septal defect was admitted to the hospital for congestive heart failure. Cardiac workup revealed chronic constrictive pericarditis; no evidence of coronary or valvular disease was found. She underwent corrective surgery for pericardiectomy. Intraoperative transesophageal echocardiography after pericardiectomy demonstrated acute development of severe mitral regurgitation, which was not preoperatively observed. She eventually required mitral valve replacement and tricuspid valve repair after conservative management failed. She recovered from the operation and was discharged. We believe that this is the first report of successful surgical management of mitral regurgitation that developed acutely after pericardiectomy.

Primary malignant pericardial mesothelioma presenting as pericardial constriction

A 55-year-old man with a history of pericardiocentesis for massive pericardial effusion of unknown etiology was admitted to our hospital because of shortness of breath and systemic edema in September 2005. Transthoracic echocardiography demonstrated the massive PE 2 cm in diameter and with several areas of thick hyperrefractile echoes arising from the pericardium. Computed tomography (CT) demonstrated a large mediastinal mass encasing the heart; a pressure of the right ventricle (RV) showed a pattern of dips and plateaus on cardiac catheterization. Pericardiocentesis was attempted, but no fluid could be aspirated. The patient's symptoms progressed day by day despite maximum pharmacological support with catecholamines and diuretics. Surgical treatment was planned to relieve the symptoms and confirm the definitive diagnosis. Pericardiectomy and partial resection of the tumor under cardiopulmonary bypass (CPB) could be performed, and this resulted in a marked relief of symptoms. Histological examination confirmed the malignant pericardial mesothelioma. In conclusion, pericardiectomy and resection of the tumor might be indicated for the relief of symptoms in a critical case presenting as pericardial constriction associated with malignant pericardial mesothelioma.