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.

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<grade 2+ preoperatively, MR increased after LVR to ≥grade 2+ leading to additional RMA during a second period of aortic cross-clamping. Early mortality in the RMA group (n=55) was 12.7% and survival at 36 months 78.2±11.2%. Early mortality in the no-RMA group (n=37) was 5.4% and survival at 36 months 81.1±12.8%. Patients in the RMA group had significantly more reduced LV function with greater LV dimensions and volumes preoperatively. Echocardiography demonstrated sustained improvement in LVEF with reduction of LV volumes in both patient groups. Recurrence of MR at late follow-up was observed in 2 patients (1 patient per group).

CONCLUSIONS

Patients with IHF eligible for LV reconstruction have MR≥grade 2+ in 44% of cases. In one-third of IHF patients with MR<grade 2+ preoperatively, MR increases to ≥grade 2+ after LVR. Concomitant mitral valve repair for MR≥grade 2+, on either preoperative echocardiography or immediately after LVR, results in favorable late clinical and echocardiographic outcome that proved to be similar to patients without concomitant mitral valve repair, despite more advanced disease.

Diaphragm plication in adult patients with diaphragm paralysis leads to long-term improvement of pulmonary function and level of dyspnea

OBJECTIVE

There is still controversy about the feasibility and long-term outcome of surgical treatment of acquired diaphragm paralysis. We analyzed the long-term effects on pulmonary function and level of dyspnea after unilateral or bilateral diaphragm plication.

METHODS

Between December 1996 and January 2006, 22 consecutive patients underwent diaphragm plication. Before surgery, spirometry in both seated and supine positions and a Baseline Dyspnea Index were assessed. The uncut diaphragm was plicated as tight as possible through a limited lateral thoracotomy. Patients with a follow-up exceeding 1 year (n=17) were invited for repeat spirometry and assessment of changes in dyspnea level using the Transition Dyspnea Index (TDI).

RESULTS

Mean follow-up was 4.9 years (range 1.2-8.7). All spirometry variables showed significant improvement. Mean vital capacity (VC) in seated position improved from 70% (of predicted value) to 79% (p<00.03), and in supine position from 54% to 73% (p=0.03). Forced expiratory volume in 1s (FEV1) in supine position improved from 45% to 63% (p=0.02). Before surgery the mean decline in VC changing from seated to supine position was 32%. At follow-up this had improved to 9% (p=0.004). For FEV1 these values were 35% and 17%, respectively (p<0.02). TDI showed remarkable improvement of dyspnea (mean+5.69 points on a scale of -9 to +9).

CONCLUSION

Diaphragm plication for single- or double-sided diaphragm paralysis provides excellent long-term results. Most patients were severely disabled before surgery but could return to a more or less normal way of life afterwards.

Mitral Valve Repair and Replacement in Endocarditis: A Systematic Review of Literature

BACKGROUND

Several observational studies have suggested a superior survival after mitral valve repair compared with replacement in patients undergoing surgery for infective endocarditis. The objective of this study was to systematically review the rate of morbidity and mortality associated with mitral valve repair or replacement in infective endocarditis.

METHODS

A Medline search was conducted for literature and a systematic review of 24 studies, reporting prognosis of patients who underwent surgery for mitral valve endocarditis, was performed. Information on the patients, type of surgery, and follow-up was abstracted using standardized protocols.

RESULTS

A total of 470 patients (39%) underwent mitral valve repair and 724 patients (61%) underwent valve replacement. Lower in-hospital mortality (2.3% versus 14.4%, relative risk: 0.16, 95% confidence interval: 0.09 to 0.30, p < 0.0001) and long-term mortality (7.8% versus 40.5%, relative risk: 0.19, 95% confidence interval: 0.13 to 0.29, p < 0.0001) were observed among patients undergoing mitral valve repair compared with replacement. In addition, the rates of early reoperation (2.2% versus 12.7%, p < 0.0001), early cerebrovascular events (4.7% versus 11.5%, p = 0.045), late reoperation (4.7% versus 8.7%, p = 0.039), late recurrent endocarditis (1.8% versus 7.3%, p = 0.0013), and late cerebrovascular events (1.6% versus 24.4%, p < 0.0001) were significantly lower after mitral valve repair. Meta-regression analysis demonstrated that mitral valve repair over replacement was associated with a better early and late prognosis after surgery. Male sex and acute surgery were (nonsignificantly) predictive of worse early outcome.

CONCLUSIONS

A systematic review of literature showed that mitral valve repair is associated with good clinical in-hospital and long-term results among patients undergoing surgery for infective endocarditis.

Degeneration of the pulmonary autograft: An explant study

OBJECTIVE

We sought to determine the histologic features of pulmonary autografts explanted after the Ross operation.

METHODS

Histologic sections of 30 explanted autografts and 8 normal heart valves were compared and semiquantitatively scored by a blinded cardiovascular pathologist.

RESULTS

Pulmonary autografts (n = 30) were explanted on average 6.1 +/- 0.6 years (median, 6.6 years; range, 0.1-11.7 years) after the Ross operation (n = 28) or removed at autopsy (n = 2). Twelve (43%) of the patients undergoing reoperation had no or negligible autograft insufficiency on early transthoracic echocardiography, 12 (43%) had grade 1 autograft insufficiency, and 4 (14%) had grade 1-2 autograft insufficiency. Valve regurgitation with root dilatation was the most common indication for reoperation after root replacement (n = 26 [93%]) and regurgitation after subcoronary implanted autografts (n = 2 [7%]). Microscopy of the autograft explants revealed normal laminar architecture and cellularity. Wall specimens were characterized by reduced and fragmented elastin and increased collagen levels (fibrosis). Medial elastin changes were associated with the presence of hypertrophic smooth muscle cells. Fibrosis was most severe in the adventitia. Intimal thickening was a common finding. Valve explants showed significant thickening caused by fibrocellular tissue on the ventricular surface and marked thickening of the free margin. An autopsy explant with normal function before death showed similar features.

CONCLUSIONS

Pulmonary autograft explants showed severe aneurysmal degeneration of the wall, which was characterized by intimal thickening, medial elastin fragmentation, and adventitial fibrosis. Valve leaflets were thickened. The presence of these features in a nonfailing explant suggests these changes represent a common mode of remodeling.

Beneficial Hemodynamic and Clinical Effects of Surgical Ventricular Restoration in Patients With Ischemic Dilated Cardiomyopathy

BACKGROUND

Surgical ventricular restoration is increasingly applied in patients with ischemic dilated cardiomyopathy. Previous studies show promising results with regard to survival and clinical outcome. However, a comprehensive midterm analysis of this approach on left ventricular (LV) and right ventricular function is not yet available. We investigated biventricular function and clinical status at 6-month follow-up.

METHODS

We investigated the effects of surgical ventricular restoration on clinical variables, LV volume, right ventricular reverse remodeling, LV dyssynchrony, tricuspid regurgitation, and pulmonary artery pressure in 21 patients with ischemic dilated cardiomyopathy (New York Heart Association class III or IV) who underwent surgical ventricular restoration and coronary artery bypass grafting. Additional surgery included mitral annuloplasty (n = 14) and tricuspid valve annuloplasty (n = 8). Clinical variables (New York Heart Association class, quality-of-life questionnaire, 6-minute hall-walk test) and echocardiographic variables were assessed at baseline and at 6 months.

RESULTS

At 6-month follow-up, all clinical variables were significantly improved. Left ventricular ejection fraction improved from 0.27 +/- 0.10 to 0.36 +/- 0.11 (p < 0.01), LV end-diastolic volume decreased from 248 +/- 78 mL to 152 +/- 50 mL (p < 0.001), and LV end-systolic volume decreased from 186 +/- 77 mL to 101 +/- 50 mL (p < 0.001). Left ventricular dyssynchrony decreased from 61 +/- 41 ms to 12 +/- 12 ms (p < 0.001). Right ventricular annular diameter decreased from 30 +/- 7 mm to 27 +/- 6 mm, right ventricular short-axis from 30 +/- 9 mm to 27 +/- 7 mm, and right ventricular long-axis from 90 +/- 7 mm to 79 +/- 10 mm (all p < 0.05). Finally, significant reductions in severity of tricuspid regurgitation (from 1.3 +/- 1.1 to 0.9 +/- 0.6; p = 0.001) and pulmonary artery pressure (42 +/- 11 mm Hg to 28 +/- 10 mm Hg; p = 0.015) were observed.

CONCLUSIONS

Surgical ventricular restoration resulted in improvement of clinical variables, significant LV volume reduction, and reduced LV dyssynchrony at 6-month follow-up. In addition, right ventricular reverse remodeling was noted with reductions in tricuspid regurgitation and pulmonary artery pressure.

Surgical ventricular restoration in patients with ischemic dilated cardiomyopathy: evaluation of systolic and diastolic ventricular function, wall stress, dyssynchrony, and mechanical efficiency by pressure-volume loops

OBJECTIVES

Surgical ventricular restoration aims at improving cardiac function by normalization of left ventricular shape and size. Recent studies indicate that surgical ventricular restoration is highly effective with an excellent 5-year outcome in patients with ischemic dilated cardiomyopathy. We used pressure-volume analysis to investigate acute changes in systolic and diastolic left ventricular function, mechanical dyssynchrony and efficiency, and wall stress.

METHODS

In 3 patient groups (total, n = 33), pressure-volume loops were measured by conductance catheter before and after surgery. The main study group consisted of 10 patients with ischemic dilated cardiomyopathy (New York Heart Association class III/IV, left ventricular ejection fraction <30%) who had surgical ventricular restoration and coronary artery bypass grafting. In this group, 7 patients had additional restrictive mitral annuloplasty. To assess potential confounding effects of restrictive mitral annuloplasty and cardiopulmonary bypass, we included a group of 10 patients (New York Heart Association class III/IV, left ventricular ejection fraction <30%) who had isolated restrictive mitral annuloplasty and a group of 13 patients with preserved left ventricular function who had isolated coronary artery bypass grafting.

RESULTS

After surgical ventricular restoration, end-diastolic and end-systolic volumes were reduced from 211 +/- 54 to 169 +/- 34 mL (P = .03) and from 147 +/- 41 to 110 +/- 59 mL (P = .04), respectively. Left ventricular ejection fraction (from 27% +/- 7% to 37% +/- 13%, P = .04) and end-systolic elastance (from 1.12 +/- 0.71 to 1.57 +/- 0.63 mm Hg/mL, P = .03) improved. Peak wall stress (from 358 +/- 108 to 244 +/- 79 mm Hg, P < .01) and mechanical dyssynchrony (from 26% +/- 4% to 19% +/- 6%, P < .01) were reduced, whereas mechanical efficiency improved (from 0.34 +/- 13 to 0.49 +/- 0.14, P = .03). End-diastolic pressure increased (from 13 +/- 6 to 20 +/- 5 mm Hg, P < .01), whereas the diastolic chamber stiffness constant tended to be increased (from 0.021 +/- 0.009 to 0.037 +/- 0.021 mL(-1), NS).

CONCLUSIONS

Surgical ventricular restoration achieves normalization of left ventricular volumes and improves systolic function and mechanical efficiency by reducing left ventricular wall stress and mechanical dyssynchrony.

Plasma natriuretic peptide levels reflect changes in heart failure symptoms, left ventricular size and function after surgical mitral valve repair

BACKGROUND AND AIM

N-terminal pro-B-type natriuretic peptide (NT-proBNP) has diagnostic and prognostic value in patients with heart failure. The present prospective study was designed to assess whether changes in NT-proBNP levels after surgical mitral valve repair reflect changes in heart failure symptoms and changes in left atrial size, left ventricular size and left ventricular function.

METHODS

The study population consisted of 22 patients (mean age: 62.8 +/- 14.2 years, 68% male) undergoing surgical mitral valve repair. Serial NT-proBNP measurements, transthoracic echocardiography and New York Heart Association (NYHA) class assessment were performed before and 6 months after surgery.

RESULTS

All patients underwent successful mitral valve repair and no patients died during follow-up. The decrease in NT-proBNP level was associated with the reduction in left atrial dimension (r = 0.72, P < 0.001), left ventricular end-systolic dimension (r = 0.63, P = 0.002), left ventricular end-diastolic dimension (r = 0.46, P = 0.031), and the increase in fractional shortening (r = - 0.63, P = 0.002). Finally, patients with decreasing NT-proBNP levels revealed a significant improvement in heart failure symptoms (NYHA class).

CONCLUSION

Changes in NT-proBNP after surgical mitral valve repair reflect changes in heart failure symptoms and changes in left atrial and ventricular dimensions and function.

Double bioprosthetic valve replacement in right-sided carcinoid heart disease

A patient with tricuspid and pulmonary regurgitation due to carcinoid syndrome successfully underwent double bioprosthetic valve replacement. This technique avoids anticoagulation treatment in a patient with hepatic dysfunction and facilitates future hepatic de-arterialization as a treatment option in carcinoid disease. Advances in treatment of carcinoid syndrome may have reduced the risk of early bioprosthetic degeneration.

Modeling ventricular function during cardiac assist: does time-varying elastance work?

The time-varying elastance theory of Suga et al. is widely used to simulate left ventricular function in mathematical models and in contemporary in vitro models. We investigated the validity of this theory in the presence of a left ventricular assist device. Left ventricular pressure and volume data are presented that demonstrate the heart-device interaction for a positive-displacement pump (Novacor) and a rotary blood pump (Medos). The Novacor was implanted in a calf and used in fixed-rate mode (85 BPM), whereas the Medos was used at several flow levels (0-3 l/min) in seven healthy sheep. The Novacor data display high beat-to-beat variations in the amplitude of the elastance curve, and the normalized curves deviate strongly from the typical bovine curve. The Medos data show how the maximum elastance depends on the pump flow level. We conclude that the original time-varying elastance theory insufficiently models the complex hemodynamic behavior of a left ventricle that is mechanically assisted, and that there is need for an updated ventricular model to simulate the heart-device interaction.

Phosphorylcholine Coating of Bypass Systems Used for Young Infants Does Not Attenuate the Inflammatory Response

BACKGROUND

Contact of blood with the artificial surfaces of the cardiopulmonary bypass (CPB) system is considered to be a main cause of complement activation. Improving the biocompatibility of the system by reduction of contact activation of blood elements and thereby producing less inflammatory response is evidently desired, especially for neonates and infants who are more susceptible to the deleterious effects of CPB. A phosphorylcholine coating, Phisio, is designed to mimic the natural interfaces of blood. The aim of this study is to compare the influence of a phosphorylcholine-coated CPB system versus an uncoated CPB system on complement activation and clinical outcomes.

METHODS

In this prospective, randomized, blind, one-center study, 28 neonates and infants with a bodyweight between 3 and 6 kg who were undergoing cardiopulmonary bypass were divided in two groups, the phosphorylcholine group and the control group. Thirteen patients were assigned to the phosphorylcholine group and 15 patients to the control group. Patients with Down syndrome, prematurity, cyanosis, or reoperation were excluded. Complement factor C3b/c, human neutrophil elastase (HNE), interleukin-6, and C-reactive protein were measured before, during, and after CPB. Duration of intensive care stay, ventilation time, highest body temperature, and inotropic medication were the clinical variables.

RESULTS

No significant differences were found between the groups for complement factor C3b/c, HNE, interleukin-6, or C-reactive protein during and after CPB. No clinical differences were observed between the groups.

CONCLUSIONS

Phosphorylcholine coating does not attenuate the complement activation during CPB in neonates and infants.

Reconstruction of the Left Ventricle After Previous Aneurysmectomy

Two patients recently underwent successful repeat left ventricular anterior aneurysmectomies at our institution. Both patients had undergone a linear repair at first operation. Over time severe heart failure relapsed and echocardiography revealed the recurrence of a voluminous antero-septo-apical aneurysm in both cases, associated with severe mitral regurgitation. Because of still preserved motion of at least three of the basal segments of the left ventricle, a repeat ventriculoplasty according to Dor and a restrictive mitral valve annuloplasty was attempted. At 6-month follow-up, the patients were in the New York Heart Association functional class I and II, respectively. Left ventricular end-diastolic diameters decreased from 73 mm to 67 mm and from 81 mm to 52 mm, and left ventricular end-systolic diameters from 61 mm to 54 mm and from 70 mm to 34 mm. Mitral regurgitation was absent.

Outcome after mitral valve repair for acute and healed infective endocarditis

OBJECTIVE

To evaluate the long-term clinical and echocardiographic outcomes after mitral valve surgery for acute and healed infective endocarditis.

METHODS

Of 37 consecutive patients presenting with native mitral valve endocarditis, mitral valve repair (MVRep) was feasible in 34 (92%) patients. In 17 (50%) patients, surgery was indicated during antibiotic therapy (acute endocarditis), whereas 17 (50%) underwent surgery after antibiotic therapy was completed (healed endocarditis). Patients were evaluated for early and long-term clinical and echocardiographic outcome.

RESULTS

In-hospital death occurred in two (6%) patients and two (6%) died during follow-up, with a 2-year survival of 100% in healed endocarditis as compared to 76% (p=0.03) in patients undergoing surgery in acute endocarditis. No patient with acute endocarditis needed repeat mitral valve surgery. Three (9%) patients underwent re-operation because of early mitral regurgitation (n=1) or late recurrent endocarditis (n=2). The average grade of mitral regurgitation was 3.8+/-0.4 (all grades 3 to 4+) before surgery and 0.6+/-0.8 during follow-up (p<0.001). Significant reductions in left atrial (from 52+/-8mm to 46+/-8mm, p=0.004), left ventricular end-diastolic (from 61+/-8mm to 54+/-8mm, p=0.001), and end-systolic dimensions (from 41+/-8mm to 36+/-9 mm, p=0.02) were observed during follow-up, compared to preoperative dimensions. Of note, significant reverse remodeling was only observed in patients undergoing surgery in healed endocarditis.

CONCLUSION

MVRep for mitral valve endocarditis is feasible with good clinical results, maintained valve competency with significant reductions in left atrial and left ventricular dimensions after surgery.

Histology of vascular myocardial wall of left atrial body after pulmonary venous incorporation

During embryonic development, the common pulmonary vein (PV) becomes incorporated into the left atrium, giving rise to separate PV ostia. We describe the consequences of this incorporation process for the histology of the left atrium and the possible clinical implications. The histology of the left atrial (LA) wall in relation to PV incorporation was studied immunohistochemically in 16 human embryos and fetuses, 1 neonate, and 5 adults. The PV wall, surrounded by extrapericardially differentiated myocardial cells, was incorporated into the LA body. After incorporation, the composition of PVs and the smooth-walled LA body wall was histologically identical. The LA appendage, however, consisted of endocardial and myocardial layers without a vessel wall component. In 2 adults, the myocardium in the LA posterior wall was absent. At the transition of the LA body and LA appendage, a smooth-walled myocardial zone lacking the venous wall was observed. This zone was histologically identical to the sinus venarum of the right atrium. In conclusion, the LA body arises by incorporation and growth of PVs, presenting with a histologically identical structure of vessel wall covered by extrapericardially differentiated myocardium of PVs. Discontinuity of myocardium may be the substrate for arrhythmias, and absence of myocardium in some patients makes this area potentially vulnerable to damage inflicted by ablation strategies. A border zone between the LA body and LA appendage is hypothesized to be the left part of the embryonic sinus venosus.

Preoperative left ventricular dimensions predict reverse remodeling following restrictive mitral annuloplasty in ischemic mitral regurgitation

OBJECTIVE

Ischemic mitral regurgitation can be treated with a restrictive mitral annuloplasty, with or without coronary revascularization. In this study, the extent of reverse remodeling of the left ventricle following this strategy is assessed, as well as the factors that influence it.

METHODS

Eighty-seven consecutive patients with ischemic mitral regurgitation and a mean ejection fraction of 32+/-10% underwent restrictive mitral annuloplasty (downsizing by two ring sizes, median ring size 26), with additional coronary revascularization in 75 patients. All underwent transthoracic echocardiography 18 months after surgery to assess residual mitral regurgitation, mitral valve gradient and left ventricular end-systolic and end-diastolic dimensions. Univariate and multivariate analysis was performed to identify predictors for reverse remodeling, defined as a 10% reduction in left ventricular dimension. Receiver-operating characteristic analysis was used to identify cut-off values for preoperative left ventricular dimensions in predicting reverse remodeling.

RESULTS

Early mortality was 8.0% (seven patients, three non-cardiac), late mortality was 7.5% (six patients, four non-cardiac). There were two reoperations (redo annuloplasty), and four readmissions for heart failure. At 29 months follow-up, NYHA class improved from 3.0+/-0.9 to 1.3+/-0.5 (P<0.01). Mitral regurgitation grade decreased from 3.1+/-0.5 to 0.6+/-0.6 at 18 months, left ventricular end-systolic dimension decreased from 52+/-8 to 44+/-11 mm (P<0.01), and end-diastolic dimension from 64+/-8 to 58+/-10mm (P<0.01). Multivariate analysis identified preoperative left ventricular end-diastolic dimension as the single best factor in predicting occurrence of reverse remodeling. For end-systolic dimension, 51mm was the optimal cut-off value to predict reverse remodeling (specificity and sensitivity 81%, area under curve 0.85); for end-diastolic dimension, the cut-off value was 65mm (specificity and sensitivity 89%, area under curve 0.92).

CONCLUSIONS

Stringent restrictive mitral annuloplasty with or without revascularization provides excellent clinical results with acceptable mortality. At 18 months follow-up, there is no significant residual mitral regurgitation. Reverse remodeling occurs in the majority of patients, but is limited by preoperative left ventricular dimensions. In patients with a left ventricular end-diastolic dimension exceeding 65mm, additional surgical procedures are necessary to try and obtain reverse remodeling in this subgroup.

MRI to Evaluate Left Atrial and Ventricular Reverse Remodeling After Restrictive Mitral Annuloplasty in Dilated Cardiomyopathy

Background— Data on reverse remodeling of the left atrium (LA) and left ventricle (LV) after restrictive annuloplasty in patients with dilated cardiomyopathy are scarce, and follow-up studies are performed with echocardiography.

Methods and Results— Twenty patients with dilated cardiomyopathy and severe mitral regurgitation selected for restrictive mitral annuloplasty underwent serial MRI studies (within 1 week before surgery, and 2 months [n =18] and 1 year [n =13] after surgery). Early mortality was 10%; all patients were free from endocarditis and thromboembolism. New York Heart Association class improved from 3.2±0.4 to 1.2±0.9. Only 1 patient developed recurrent severe mitral regurgitation during follow-up and it was re-repaired. LA end-systolic volumes decreased significantly over time (from 165±48 mL to 109±23 mL to 111±28 mL; P <0.01), as did LA end-diastolic volumes (from 92±32 mL to 71±22 mL to 75±17 mL; P =0.01). LV end-diastolic volumes decreased significantly (from 244±56 mL to 184±54 mL to 195±67 mL; P <0.01), whereas end-systolic volumes did not change significantly. LV ejection fraction increased significantly (from 35±8% to 46±13% to 46±15%; P <0.01) and LV mass decreased significantly (from 150±43 grams to 132±39 grams to 136±33 grams; P =0.02).

Conclusion— Restrictive annuloplasty in patients with dilated cardiomyopathy yielded excellent clinical results associated with significant LA and LV reverse remodeling over time as demonstrated by MRI.

Underestimation of severity of mitral regurgitation with varying hemodynamics

Transesophageal echocardiography (TEE) is a valuable technique to assess mitral valve anatomy and the mechanism of mitral regurgitation (MR). We present the case of a 35-year-old woman with severe MR due to restrictive motion of the posterior mitral leaflet, who was referred for mitral annuloplasty. Under physiologic circumstances, a severe (grade 3+) MR was present, whereas in the operating room during general anesthesia, the MR had disappeared almost completely. The downgrading of MR due to general anesthesia and the associated mechanisms of this phenomenon are discussed in this case.

Acute hemodynamic effects of restrictive mitral annuloplasty in patients with end-stage heart failure: Analysis by pressure-volume relations

OBJECTIVE

Recent studies show beneficial long-term effects of restrictive mitral annuloplasty in patients with end-stage heart failure. However, concerns are raised about possible adverse effects on early postoperative systolic and diastolic function, which might limit application of this approach in patients with heart failure. Therefore we evaluated the acute effects of restrictive mitral annuloplasty on left ventricular function by using load-independent pressure-volume relations.

METHODS

In 23 patients (heart failure, n = 10; control, n = 13) we determined left ventricular systolic and diastolic function before and after surgical intervention by means of pressure-volume analysis with a conductance catheter. All patients with heart failure underwent stringent restrictive mitral annuloplasty (2 sizes smaller than the measured size), and 4 received additional coronary artery bypass grafting. Transesophageal echocardiography was used for evaluation of valve repair. Patients with preserved left ventricular function who underwent isolated coronary artery bypass grafting served as control subjects.

RESULTS

Restrictive mitral annuloplasty (ring size, 25 +/- 1) restored leaflet coaptation (8.0 +/- 0.2 mm) with normal pressure gradients (2.9 +/- 1.8 mm Hg). Restrictive mitral annuloplasty did not change cardiac output (5.0 +/- 1.8 to 5.3 +/- 0.9 L/min, P = .516), left ventricular ejection fraction (29% +/- 5% to 32% +/- 8%, P = .315), or end-systolic elastance (0.86 +/- 0.50 to 0.99 +/- 1.05 mm Hg/mL, P = .688). After restrictive mitral annuloplasty, end-diastolic volume tended to decrease (237 +/- 89 to 226 +/- 52 mL, P = .564), whereas end-diastolic pressure remained unchanged (14 +/- 6 to 15 +/- 5 mm Hg, P = .356). Diastolic chamber stiffness tended to increase (0.027 +/- 0.035 to 0.041 +/- 0.047 mL -1 , P = .542) but not significantly. Peak left ventricular wall stress was unchanged (356 +/- 91 to 346 +/- 85 mm Hg, P = .668). Baseline values in the control group were different, but changes in most parameters after surgical intervention showed similar nonsignificant trends.

CONCLUSION

Mitral valve repair by means of restrictive mitral annuloplasty effectively restores mitral valve competence without inducing significant acute changes in left ventricular systolic or diastolic function in patients with end-stage heart failure.

Results of the Ross operation in a pediatric population

OBJECTIVE

To analyse the results of the mid-term clinical and echocardiographic follow-up of the pediatric Ross operation.

METHODS

Echo-Doppler follow-up of 53 consecutive pediatric Ross procedures performed between 1994 and 2003. Median age was 9.7 years at time of operation (2 weeks-17.7 years). Six patients were younger than 3 months. Median age at follow-up was 15.6 years. Aortic valve/left ventricular outflow tract (LVOT) anomalies were congenital in 49 (92%). Seventy percent had previous surgery or balloon valvuloplasty. Root replacement was used in all. Thirteen patients (25%) had LVOT enlargement. Mean cross-clamp time was 113 (69-189) minutes.

RESULTS

Early mortality occurred in 3 patients after emergency surgery following balloon failure (n=1) and extended Ross following interrupted arch/VSD repair (n=2). Late mortality was due to LV fibroelastosis in 2 patients and complicated pulmonary artery stenting in another. RVOT reoperations were required because of late homograft obstruction in 2 patients and because of pulmonary artery stenosis in another. Five patients (9.4%) were reoperated for pulmonary autograft dilatation (n=3) and for leaflet fibrosis or perforation (n=2). Autografts were repaired in two patients, while a mechanical valve was inserted in 3 cases. At 9 years the actuarial survival and event free survival were 89 and 74%, respectively. At last follow-up 90% of autograft diameters indexed to body surface area was above the 90th percentile of normal aortic root diameters. LVOT and RVOT gradients were low and autograft insufficiency was trivial to mild in 84% and mild to moderate in 16%. Autograft stenosis was not noticed.

CONCLUSIONS

The pediatric Ross procedure remains an important tool but autograft dilatation also occurs in the pediatric population. The significance of this finding has yet to be determined.

Left ventricular function and chronotropic responses after normothermic cardiopulmonary bypass with intermittent antegrade warm blood cardioplegia in patients undergoing coronary artery bypass grafting

OBJECTIVE

Recent studies indicate that normothermic cardiopulmonary bypass (CPB) with intermittent antegrade warm blood cardioplegia (IAWBC) may have metabolic and clinical advantages, but limited data exist on its effects on myocardial function. Therefore, we investigated the acute effects of this approach on systolic and diastolic left ventricular function and on chronotropic responses.

METHODS

In 10 patients undergoing isolated CABG we obtained on-line left ventricular pressure-volume loops using the conductance catheter before and after normothermic CPB with IAWBC. Steady state and load-independent indices of left ventricular function derived from pressure-volume relations were obtained during right atrial pacing (80-100-120 beats/min) to determine baseline systolic and diastolic function and chronotropic responses.

RESULTS

The mean time of CPB was 105+/-36 min (median 103, range 60-167 min) with a mean aortic cross-clamp time of 75+/-27 min (median 69, range 43-129 min). Baseline (80 beats/min) end-systolic elastance (E(ES)) did not change after CPB (1.22+/-0.53 to 1.12+/-0.28 mm Hg/ml, P>0.2), while the diastolic chamber stiffness constant (k(ED)) significantly increased (0.014+/-0.005 to 0.040+/-0.007 ml-1, P=0.018) and relaxation time constant (tau) significantly decreased (61+/-3 to 49+/-2 ms, P=0.004). Before CPB, incremental atrial pacing had no significant effects on E(ES) and tau but significant negative effects on kED (0.014+/-0.005 to 0.045+/-0.012 ml-1, P=0.013). After CPB, atrial pacing had significant positive effects on E(ES), tau and kED (E(ES): 1.12+/-0.28 to 2.60+/-1.54 mm Hg/ml, P=0.021; tau: 49+/-2 to 45+/-2 ms, P=0.009; kED: 0.040+/-0.007 to 0.026+/-0.005 mm Hg, P=0.010), indicating improved systolic and diastolic chronotropic responses.

CONCLUSION

On-pump normothermic CABG with IAWBC preserved systolic function, increased diastolic stiffness, and improved systolic and diastolic chronotropic responses. Normalization of the chronotropic responses post-CPB is likely due to effects of successful revascularization and subsequent relief of ischemia.

Accurate quantitation of regurgitant volume with MRI in patients selected for mitral valve repair

OBJECTIVE

Echocardiography, the currently preferred diagnostic approach for mitral valve regurgitation, cannot accurately quantify the amount of regurgitation. Flow quantification with MRI is possible, but the conventional method (1-directional velocity-encoding) acquires the flow at a fixed location during the cardiac cycle, which is not necessarily the location of the mitral valve during the whole cycle. In this study, the exact flow through the mitral valve was quantified with a 3-directional velocity-encoded MRI approach.

METHODS

Ten patients with severe mitral valve regurgitation (class 3-4+with echocardiography) resulting from systolic restrictive motion of both leaflets (Carpentier IIIb) which were selected for valve repair and 10 healthy volunteers without cardiac valvular disease confirmed with echocardiography were included in this study. The intra-ventricular flow was sampled with a radial stack of six acquisition planes parallel to the long-axis of the left ventricle. Three-directional velocity-encoded MRI was performed resulting in the intra-ventricular flow velocity vector field for 30 phases during the cardiac cycle. The position of the mitral valvular plane in this vector field was indicated manually for each phase. Velocity values perpendicular to this plane determined the flow through the mitral valve. Both the 3-directional encoded mitral valve flow and the 1-directional encoded mitral valve flow were compared with the flow determined with MRI at the ascending aorta.

RESULTS

One-directional velocity-encoded MRI showed a mean overestimation (P<0.01) of 25 ml/cycle compared to the aortic flow. Correlation was very poor (r(P)=0.15, P=0.68). The 3-directional velocity-encoded MRI on the other hand, showed no over/underestimation and a good correlation (r(P)=0.91, P<0.01 for volunteers, r(P)=0.90, P<0.01 for patients). The regurgitant flow fractions were between 3 and 30%.

CONCLUSION

With 3-directional velocity-encoded MRI, measurement of the flow through the mitral valve is accurate and reproducible. This is a valuable tool for diagnosing and absolute quantification of regurgitant volume.

Mitral valve regurgitation: accurate blood flow quantification with MRI

BACKGROUND

The quantification of transvalvular blood flow through the mitral valve (MV) and regurgitant flow in particular is difficult with echocardiography, which is the method of choice to diagnose patients selected for valve repair or replacement. With magnetic resonance imaging, information on the intraventricular blood flow can be obtained. Several scanning techniques have attempted to assess the regurgitant flow. These techniques either do not directly assess the complete flow through the MV, or they do not measure the flow at the location of the valve.

AIM

To investigate the accuracy of a novel method using three-directional velocity-encoded MRI to acquire the transvalvular blood flow directly from the intraventricular blood flow field, also representing the regurgitant flow during systole.

METHODS

Ten volunteers without cardiac valvular disease were recruited. The transvalvular MV flow volume was measured with three-directional velocity-encoded MRI (3-dir MV flow).

RESULTS

The transvalvular flow measurements correlate very well with the flow measured in the aorta (r_p=0.92, p<0.01). The small differences (mean -5±7 ml) are insignificant (p=0.06) and demonstrate the high accuracy of the new method. Intra- and inter-observer studies showed non-significant mean differences of 0.9±5.1 ml and 1.3±5.6 ml, respectively, thereby proving the high reproducibility.

CONCLUSION

Three-directional velocity-encoded MRI is a patient-friendly and easy-to-use method suitable for quantifying the regurgitant MV flow in clinical practice.

Exercise therapy after coronary artery bypass graft surgery: a randomized comparison of a high and low frequency exercise therapy program

BACKGROUND

Postoperative exercise therapy aims at recovering, as soon as possible, independence in the basic physical activities; but the type, intensity, and therefore the costs of the programs, vary widely. The aim of this study was to compare the effectiveness of a low frequency (once daily, not in the weekend) program with a high frequency (twice daily, including the weekend) one and to assess whether the latter would yield sufficient benefit for the patient to justify higher costs in material and personnel (physiotherapists) after uncomplicated coronary artery bypass graft (CABG) surgery.

METHODS

Two-hundred and forty-six patients were randomly allocated to either a low or high frequency exercise program. Endpoints were the functional level as measured by the achievement of five activity milestones, the patient's independence (functional independence measures [FIM]) as assessed by a structured interview, the amount of daily physical activity (activity monitor), and patient satisfaction (questionnaire). Except for patient satisfaction, all measurements were done in the first week after surgery.

RESULTS

Patients with the high frequency exercise program achieved functional milestones faster than patients with the low frequency exercise program (p = 0.007). The frequency of the exercise program had no influence on functional independence as measured with the FIM or quantity of physical activity. The satisfaction degree was greater in the high frequency group (p = 0.032), although the low frequency group was not dissatisfied.

CONCLUSIONS

A high frequency exercise program leads to earlier performance of functional milestones and yields more satisfaction after uncomplicated CABG surgery and this should lead to an earlier discharge. On the other hand, if the shortage of physiotherapists remains unchanged or even increases, the low frequency program also yields excellent functional results, albeit at the cost of a somewhat longer hospital stay: but it would allow a sensible redistribution of the physiotherapists activity towards complicated and, therefore, more demanding patients.

Long-term follow-up of coronary artery bypass grafting in three-vessel disease using exclusively pedicled bilateral internal thoracic and right gastroepiploic arteries

BACKGROUND

Considerable data now exist that show that coronary artery bypass grafting with bilateral internal thoracic artery (ITA) grafts produce better outcomes than the use of a single ITA graft. The benefit of a third arterial graft has been less well established. Therefore this article describes the survival and cardiac-related event-free survival in patients having bilateral ITA and gastroepiploic artery (GEA) grafting for 3-vessel disease.

METHODS

From November 1992 to May 2002, 201 patients (mean age 53 +/- 7 years) presented with 3-vessel disease and received exclusively bilateral internal thoracic (ITAs) and right gastroepiploic (GEA) arteries as pedicled grafts for coronary artery bypass procedure. Twenty-seven (13%) patients were not elective, 10 (5%) were reoperations, 115 (57%) had one or more myocardial infarction, 21 (10%) had diabetes. In total 733 anastomoses were constructed (3.7/patient), with sequential grafting in 124 (62%) patients. The clinical follow-up was complete. The patients were followed for up to 10 years (mean 6.4 +/- 2.7 years).

RESULTS

Ten-year actuarial survival (including in-hospital death) was 87%. The actuarial freedom from angina pectoris, after hospital discharge, was 97% and 86% at 5 and 10 years respectively. None of the patients needed a repeat surgical revascularization after leaving the hospital, whereas 9 (5%) patients underwent a percutaneous transluminal coronary angioplasty. At 5 years 86% and at 10 years 69% of the patients remained free of any cardiac-related event.

CONCLUSIONS

The results of this study clearly indicate that the exclusive and extensive use of pedicled bilateral ITA and GEA in coronary bypass grafting provides excellent 10-year patient survival and functional improvement in terms of freedom from return of angina pectoris and, more impressive, freedom from any cardiac-related event. Our findings clearly corroborate the concomitant use of bilateral ITA and GEA grafts in selected patients with 3-vessel disease.

Quantification of left ventricular mechanical dyssynchrony by conductance catheter in heart failure patients

Mechanical dyssynchrony is an important codeterminant of cardiac dysfunction in heart failure. Treatment, either medical, surgical, or by pacing, may improve cardiac function partly by improving mechanical synchrony. Consequently, the quantification of ventricular mechanical (dys)synchrony may have important diagnostic and prognostic value and may help to determine optimal therapy. Therefore, we introduced new indexes to quantify temporal and spatial aspects of mechanical dyssynchrony derived from online segmental conductance catheter signals obtained during diagnostic cardiac catheterization. To test the feasibility and usefulness of our approach, we determined cardiac function and left ventricular mechanical dyssynchrony by the conductance catheter in heart failure patients with intraventricular conduction delay ( n = 12) and in patients with coronary artery disease ( n = 6) and relatively preserved left ventricular function. The heart failure patients showed depressed systolic and diastolic function. However, the most marked hemodynamic differences between the groups were found for mechanical dyssynchrony, indicating a high sensitivity and specificity of the new indexes. Comparison of conductance catheter-derived indexes with septal-to-lateral dyssynchrony derived by tissue-Doppler velocity imaging showed highly significant correlations. The proposed indexes provide additional, new, and quantitative information on temporal and spatial aspects of mechanical dyssynchrony. They may refine diagnosis of cardiac dysfunction and evaluation of interventions, and ultimately help to select optimal therapy.

MRI evaluation of left ventricular function in anterior LV aneurysms before and after surgical resection

OBJECTIVES

Whether resection of a left ventricular (LV) aneurysm leads to improved global LV function remains controversial. Echo-planar magnetic resonance imaging (MRI) is a sensitive tool to detect changes in LV function. Therefore, the purpose of the present study was to monitor changes in global LV function and anatomy following LV aneurysm resection using MRI.

METHODS

The present study includes 12 patients with an anterior LV aneurysm. Echo-planar MRI evaluation of LV function was performed before surgery and 6 weeks and 3 months after LV remodeling surgery, in most patients combined with coronary artery by-pass grafting (CABG).

RESULTS

Following LV aneurysm resection, a decrease was found in end-diastolic volume from 238+/-63 to 180+/-54 ml at 6 weeks to 198+/-51 ml (P<0.05) at 3 months and in end-systolic volume from 156+/-62 to 105+/-44 to 111+/-43 ml (P<0.01), whereas the ejection fraction increased from 37+/-11 to 43+/-9 to 45+/-10% (P<0.01).

CONCLUSIONS

LV remodeling surgery leads to a cardiac anatomy more closely resembling normal anatomy. As a consequence, LV contractile function improved significantly. In addition, it was shown that echo-planar cardiac MRI is a sensitive tool to study subtle changes in heart anatomy and function. In this preliminary experience, pre- and postoperative MRI has demonstrated that LV remodeling surgery may restore cardiac anatomy and improve LV contractile function.

Structural degeneration of pulmonary homografts used as aortic valve substitute underlines early graft failure

OBJECTIVES

The limited availability of donor valves and experimental evidence that pulmonary valves can withstand systemic pressure made us use cryopreserved pulmonary homografts as aortic valve substitutes. We observed a high incidence of early reoperation because of severe graft insufficiency due to cuspal tears. The mid-term results are evaluated in this study and histological analysis of explanted homografts is performed to investigate the cause of graft failure.

METHODS

From December 1991 to April 1994, 16 patients (13 male; mean age 37.3 years, range 21-59 years) underwent aortic valve replacement with a cryopreserved pulmonary homograft. The indication was endocarditis (n = 4), bioprosthesis degeneration (n = 3) or congenital aortic valve disease (n = 9). All homografts were implanted freehand in the subcoronary position. All patients were contacted for follow-up and recent echo-Doppler studies were reviewed. Six explanted homografts were examined microscopically using routine histological techniques to analyze changes in cell population, collagen and elastic fiber structure.

RESULTS

Follow-up was complete in all patients. Reoperation was required in ten patients because of severe graft incompetence (mean implantation time 5.9 years, range 2.8-8.0 years). In two patients, recurrent endocarditis was the cause of graft failure. In the other eight patients the leaflets looked pliable and thin with gross tearing in one or more cusps. The histopathologic changes observed were remarkably similar in all examined grafts: the cusp tissue was almost non-cellular and the collagen fiber structure had mostly disappeared. At the site of rupture, the tissue had become thin with strongly degenerated collagen and elastic fiber structure. In the six patients with a homograft remaining in situ, echo-Doppler showed trivial to mild insufficiency in five cases and moderate to severe in one case, whereas no significant gradients were observed.

CONCLUSIONS

We concluded that structural reduction of cell number and degenerative alterations in the molecular composition of the extracellular matrix in valve tissue is the main cause of early graft failure in this series. The use of cryopreserved pulmonary homografts in the systemic circulation is therefore not advised.

The pathology of fresh and cryopreserved homograft heart valves: an analysis of forty explanted homograft valves

OBJECTIVE

Tissue degeneration reduces the durability of aortic and pulmonary homograft heart valves. Homograft valves can evoke cellular and humoral immune responses that might be detrimental to the valve tissue. Analyzing explanted homograft valves helps in understanding the different factors that eventually lead to tissue degeneration.

METHODS

A total of 40 homografts was acquired from patients whose grafts had been explanted because of stenosis (n = 22), insufficiency (n = 8), paravalvular leakage (n = 4), other technical problems (n = 4), noncardiac death (n = 1), and stenosis with endocarditis (n = 1). The period of implantation varied from 14 days to 16 years (median, 4 years). Cryopreserved valves (n = 31) were, in the majority, derived from beating-heart donors, whereas the fresh valves were sterilized with antibiotics and stored at 4 degrees C for an average of 32 days. Four unimplanted cryopreserved valves, 1 native aortic valve, and 1 native pulmonary valve were used as references. Analysis included macroscopy, light microscopy with routine hematoxylin and eosin staining (cellularity and tissue structure), and immunohistochemical studies to allow identification of macrophages (CD68) and T lymphocytes (CD3), endothelial cells, leukocyte adhesion molecules (CD54, CD106, and CD62E), and immunoglobulin (IgG) and complement factor (C3) depositions. In situ hybridization for the Y chromosome was performed in 10 cases, with host-donor sex mismatch, to distinguish between host and donor cells. The outcomes of histology and immunohistochemistry were related to clinical factors, such as implantation time and reason for explantation.

RESULTS

In the first year after implantation, a strong reduction in cellularity of the valve tissue was observed, with almost acellular tissues after 1 year. Trilaminar tissue architecture disappeared with the same speed, whereas endothelial cells were almost absent in all explants. Macrophages and T lymphocytes were encountered in 85% and 78% of the leaflets, respectively. Expression of leukocyte adhesion molecules was low in almost all grafts, and IgG and C3 depositions were not increased. Valve tissue cellularity consisted mainly of ingrown host cells when the implantation time exceeded 1 year.

CONCLUSIONS

During the first year of implantation, homograft valves rapidly lose their cellular components and normal tissue architecture. A low-grade inflammatory response was observed, but no convincing evidence of immune-mediated injury was found.