Transient sinus node dysfunction after the Cox-maze III procedure in patients with organic heart disease and chronic fixed atrial fibrillation.

OBJECTIVES: This prospective study examined types, frequency and time dependency of the electrophysiologic manifestation of the sinus node dysfunction after the Cox-maze III procedure--the technique of choice for the management of medically refractory atrial fibrillation-in patients with organic heart disease, chronic fixed atrial fibrillation and no preoperatively overt dysfunction of the sinus node. BACKGROUND: The original maze procedure was modified twice in order to reduce the high incidence of the sinus node inability to generate an appropriate sinus tachycardia in response to maximal exercise, and occasional left atrial dysfunction. Despite these modifications, postoperative disturbance of sinus node function can be frequently observed. METHODS: In 15 adult patients, standard electrocardiogram, 24-h Holter monitoring, power spectral analysis of heart variability, exercise testing, Valsalva maneuver and rapid positional changes were performed 3, 6 and 12 months after the Cox-maze III procedure and mitral valve surgery or closure of atrial septal defect. RESULTS: Electrocardiographic manifestations of sinus node dysfunction were identified in 12 patients at 3 months, in 6 patients at 6 months, and in 0 patients at 12 months after surgery. The heart rate response to exercise during the first 6 months was reduced in the maze group and became fully normal at 12 months. Power spectral analysis of heart rate variability showed very low power values at 1 month with inhibited cardiac autonomic activity and no response on sympathetic stress. A potential of recovery of cardiac autonomic activity was documented 12 months after surgery. CONCLUSIONS: The manifestations of sinus node dysfunction following the Cox-maze III procedure were time dependent and their frequency and intensity progressively decreased and disappeared within 12 months after surgery.

Decreased plasma concentration of brain natriuretic peptide as a potential indicator of cardiac recovery in patients supported by mechanical circulatory assist systems.

OBJECTIVES: We sought to investigate the relationship between the plasma concentration of brain natriuretic peptide (BNP), echocardiographic findings and the clinical outcome of patients supported with ventricular assist devices (VADs) to determine the role of BNP as a predictor for cardiac recovery. BACKGROUND: Ventricular unloading in patients with end-stage heart failure supported by VADs may lead to myocardial recovery. The BNP is produced in the myocardium in response to chronic volume overload, but the effects on it of ventricular unloading by VADs are largely unknown. METHODS: Twenty-one patients diagnosed with nonischemic cardiomyopathy and supported by VADs were evaluated for echocardiographic data and blood chemistry including BNP. They were divided into patients who died while on mechanical support (group I; n = 9), patients who were transplanted (group II; n = 8) and patients who were successfully weaned off the system and did not require transplantation (group III; n = 4). RESULTS: Brain natriuretic peptide plasma concentrations decreased significantly after initiation of mechanical circulatory support (p = 0.017). Furthermore, the changes in BNP plasma concentrations showed a faster decrease to normal levels within the first week after implantation of the VAD in patients who were weaned off the system (group III) compared to patients in group I and group II. CONCLUSIONS: This study shows that ventricular unloading with VADs decreases BNP plasma concentrations in patients who suffer from end-stage heart failure. Furthermore, we hypothesize that an early decrease of BNP plasma concentration may be indicative of recovery of ventricular function during mechanical circulatory support.

The Cox maze iii procedure: parallel normalization of sinus node dysfunction, improvement of atrial function, and recovery of the cardiac autonomic nervous system.

OBJECTIVE: The Cox maze III procedure includes isolation of the pulmonary veins and multiple incisions in both atria in what corresponds to partial autotransplantation and partial denervation of the heart. The aim of this prospective longitudinal study was to identify physiologic effects of reinnervation on changes in heart rate at rest and in response to various stimulations and on atrial function after the Cox maze III procedure. PATIENTS AND METHODS: Power spectral analysis of heart rate variability, exercise testing, 24-hour Holter monitoring, electrocardiography, and transthoracic and transesophageal echocardiography were performed in 30 adult patients after the combined Cox maze III procedure and mitral valve surgery (maze group). They were prospectively followed up at 1, 3, 6, and 12 months after the operation. The results were compared with those of 15 heart transplant recipients (transplant group) and normal probands (healthy adults, n = 12). RESULTS: The physiologic effects of denervation with no differences in cardiac autonomic activity between the groups were seen early after the operation. Later, evidence of autonomic reinnervation was observed only in the maze group but not in the transplant group. Inappropriate heart rate responses during physical exercise were clearly evident in both groups after 1 and 3 months, with progressive improvement seen between 6 and 12 months only in the maze group. Left atrial function after the Cox maze procedure improved parallel to the recovery of sinus node function. CONCLUSION: Progressive improvement of sinus node function and atrial contractions with significant functional normalization 1 year after the Cox maze procedure corresponded to functional reinnervation and recovery of the autonomic nervous system.

Clinical heart transplantation without routine endomyocardial biopsy.

In a prospective clinical study, routine endomyocardial biopsy (EMB) for early detection of cardiac allograft rejection was replaced by two noninvasive diagnostic techniques. In 32 patients who underwent transplantation during a 6-month period, intramyocardial electrogram (IMEG) amplitude was recorded with the telemetry function of a dual-chamber pacemaker system. An amplitude decrease of more than 8% below the individual range of variability in overnight long-term recordings served as an indicator of rejection. A prolongation of the time interval Te--the time span between maximal posterior wall contraction and peak retraction velocity--of more than 20 msec was used as an additional indicator of rejection-related left ventricular dysfunction. For patient safety, routine EMBs were still performed but remained undisclosed to the transplantation team. The pathologist was asked to intervene in cases of discrepancies between biopsy results and medical decisions, but no such intervention was necessary. Twenty-seven rejection episodes were treated medically, of which 22 were diagnosed noninvasively. In four patients, EMB, ordered because noninvasive parameters remained inconclusive, led to medical treatment. No false negative IMEG results were observed. Retrospective correlation with rejection gave a 100% negative predictive value for IMEG and a 96.9% negative predictive value for echocardiographic diagnosis. We conclude that omission of a schedule of routine biopsies is justified, if the described techniques of IMEG and echocardiography are meticulously applied and indicate normal cardiac function. EMB remains indicated if noninvasive parameters are not conclusive or if false-positive IMEG results, which were observed in the presence of infection or arrhythmias, are suspected. The frequency of EMB can be reduced by 90%, compared to conventional routine biopsy schedules. Diagnostic safety is increased because the additional information gained from IMEG and echocardiography is helpful in the interpretation of EMBs.

Electric myocardial impedance registration in humoral rejection after heart transplantation.

BACKGROUND: Because of the absent lymphocyte infiltrate, humoral-mediated rejection after heart transplantation is not diagnosed by the usual staining technique (hematoxylin-eosin method) of the endomyocardial biopsy specimen. However, humoral rejection is characterized by a distinct myocardial edema caused by capillary leakage. Because tissue edema increases the electric myocardial impedance of the corresponding tissue compartment the electric myocardial impedance method should be able to detect these episodes more reliably than biopsy. METHODS: To evaluate this hypothesis eight DLA-matched beagle dogs were subjected to heterotopic neck heart transplantation after multiple sensitization by skin grafts of the heart donor. For electric myocardial impedance registrations rectangular impulses (wide 1 msec) were applied over two intramyocardial electrodes and the impulse response was registered. Day-to-day comparisons were made and an increase of electric myocardial impedance of 10% or more was used as an indicator of rejection. To assess the influence of edema caused by electrode implantation, cortisone administration, narcosis, ischemia, or reperfusion on the electric myocardial impedance, identical electrodes were implanted in the native hearts of five additional dogs via lateral thoracotomy. These animals each received 100 mg methylprednisolone between postoperative days 20 and 22 and underwent heterotopic neck heart transplantation on postoperative day 28 without previous sensitization (protocol 2). Electric myocardial impedance electrodes were also implanted in these allografts (protocol 3). After transplantation myocardial biopsies were done every 2 days and the samples graded according to the International Society for Heart and Lung Transplantation classification in all dogs. RESULTS: Despite triple-drug immunosuppression (cyclosporine A, prednisolone, azathioprine) humoral rejection developed in all sensitized dogs as established by immunofluorescent staining of myocardial biopsy samples and functional deterioration. All episodes were diagnosed by electric myocardial impedance (sensitivity 100%), whereas only in one case the biopsy specimen was positive (International Society for Heart and Lung Transplantation grade > 1) (sensitivity 12.5%). All eight episodes could be treated successfully, that is, myocardial performance and electric myocardial impedance showed an immediate and full recovery. During the first 12 days none of the nonsensitized dogs exhibited rejection. Protocol 2 indicated that narcosis and the administration of cortisone did not per se have an influence on electric myocardial impedance and the influence of electrode implantation was negligible. Contrarily, edema caused by ischemia and reperfusion during transplantation (protocols 1 and 3) led to a significant increase in electric myocardial impedance. However, after 2 days this edema had faded away such that it no longer disturbed rejection diagnosis. CONCLUSION: We conclude that the registration of the electric myocardial impedance diagnoses humoral rejection episodes after heart transplantation not only reliably but also early, that is, before the onset of irreversible graft damage.

Treatment of humoral rejection after heart transplantation.

BACKGROUND: Until a few years ago, the incidence of humoral rejection after heart transplantation was underestimated. These episodes were frequently very aggressive and often fatal, because the maintenance and emergency immunosuppression available at the time only inadequately covered the humoral branch of the immune response. In spite of individual case reports, the effects of blood purification procedures or cyclophosphamide in this situation can only be insufficiently estimated. METHODS: To evaluate this therapy concept, 20 dog-lymphocyte-antigen-matched dogs underwent heterotopic neck-heart transplantation. Fourteen dogs underwent transplantation after having been previously sensitized through multiple skin transplantations, 6 dogs were not sensitized (control). The animals received an induction with 3x 250 mg prednisolone, as well as triple immunosuppression (cyclosporine, azathioprine, and cortisone). Biopsy (light microscopy, immunofluorescence), intramyocardial voltage, electric myocardial impedance (>200 kHz, <10 kHz), and echocardiographic (left ventricular wall thickness, diastolic relaxation velocity) examinations were performed daily to monitor rejection. Rejection therapy was continued for 3 days according to the following regimen: apheresis, cortisone boluses (CB), and cyclophosphamide in group A1 (n = 4), apheresis and CB without cyclophosphamide in group A2 (n = 4), and CB only in group C (n = 6). The subsequent course under triple immunosuppression was then observed. RESULTS: In the sensitized animals the onset of severe humoral rejection on the fifth day deteriorated cardiac function down to 75% (70% to 80%) of the initial values. In groups A1 and A2, apheresis resulted in recovery to near-control values (89% to 94%) within two hours, and indeed to complete recovery (97% to 101%) after the second apheresis, that is, within 1 day. In group C recovery was delayed (2 days) and incomplete (84% to 91 %). After therapy was discontinued, rejection-related functional deterioration recurred immediately in group C, and from 2 to 3 days after apheresis, regardless of whether cyclophosphamide therapy was performed (group A1) or not (group A2). In the control group all animals showed a rejection-free posttransplantation course. CONCLUSIONS: By diluting inflammatory mediators, apheresis leads to a rapid improvement in cardiac function during severe humoral rejection after head transplantation. Neither apheresis nor cyclophosphamide therapy are able to have an immediate positive influence on the activation of the immune cascade and to prevent an ongoing rejection.

Decision-making in end-stage coronary artery disease: revascularization or heart transplantation?

BACKGROUND: Left ventricular function is the most important predictor of survival in patients with coronary artery disease. It is also an important indicator for hospital and late mortality after operation for endstage coronary artery disease. METHODS: Between April 1986 and December 1994, 514 patients with end-stage coronary artery disease and left ventricular ejection fraction between 0.10 and 0.30 underwent coronary artery bypass grafting at the German Heart Institute Berlin. Two hundred twenty-five of these patients had been referred as possible candidates for heart transplantation. The prime criterion for bypass grafting was ischemia diagnosed by myocardial scintigraphy and echocardiography ("hibernating myocardium"). RESULTS: Operative mortality for the group was 7.1%. The actuarial survival rate was 90.8% after 2 years, 87.6% after 4, and 78.9% after 6. Left heart catheterizations performed 1 year after the operation showed that left ventricular ejection fraction had increased from a mean of 0.24 +/- 0.03 preoperatively to 0.39 +/- 0.06 postoperatively (p < 0.0001). Preoperatively 91.6% of the patients were in New York Heart Association (NYHA) class III or IV; 6 months postoperatively 90.2% of the surviving patients were in NYHA class I or II. Two hundred thirty-one patients with end-stage coronary artery disease and predominant heart failure underwent heart transplantation. Their actuarial survival rate was 74.9% after 2 years, 73.2% after 4, and 68.9% after 6. All of the patients could be recategorized into NYHA class I or II after the operation. CONCLUSIONS: We conclude that coronary artery bypass grafting and heart transplantation can be used successfully to improve the life expectancy of patients with end-stage coronary artery disease. Coronary artery bypass grafting leads to an excellent prognosis for these high-risk patients when the myocardium is preoperatively identified as being viable.

Identification of P waves after the Cox-maze procedure: significance of right precordial leads V3R through V6R.

BACKGROUND: The maze circuit lengthens the period of atrial depolarization and may lead to small or absent P waves, which may not be readily apparent in a standard 12-lead electrocardiogram. In this prospective study, we investigate if the right precordial leads V3R through V6R can improve detection of P waves and identification of atrial electrical activity. METHODS: Standard 12-lead electrocardiograms (with leads I through III, aVR, aVL, aVF, and V1 through V6) and right precordial electrocardiograms (V3R through V6R) were recorded in 30 consecutive patients during the first 5 postoperative days and 1, 3, 6, 12, and 24 months after combined Cox-maze III procedure and mitral valve surgery. The P wave identification as an indication of atrial electrical activity and atrial contraction was proved by transesophageal echocardiographic identification of atrial contractions. RESULTS: Despite echocardiographically identifiable atrial contractions, the P waves were not visible on standard 12-lead electrocardiograms in 7 (23%) patients after 1 and 3 months, and in 4 patients after 6 months. In contrast, right precordial electrocardiograms showed P waves in all of these patients that were best seen in lead V4R. Twelve and 24 months postoperatively, only 2 patients had no visible P waves in the standard leads that were still present in the right precordial leads. However, if P waves were easily identifiable in standard 12-lead electrocardiograms (23 patients at 1 and 3 months after surgery), the right precordial leads showed P waves only in 15 patients. CONCLUSIONS: Right precordial electrocardiogram with leads V3R through V6R is a helpful tool for visualizing P waves after the Cox-maze procedure. Standard 12-lead electrocardiogram should be combined with right precordial electrocardiogram in all patients after the Cox-maze procedure.

Mitral valve reconstruction and replacement for ischemic mitral insufficiency: seven years' follow up.

BACKGROUND AND AIMS OF THE STUDY: Patients with ischemic mitral incompetence have a high operative risk whether the valve is repaired or replaced. The advantage of repair over replacement is unclear in this subgroup of patients. METHODS: Between April 1986 and December 1998, 337 patients underwent surgery for ischemic mitral valve insufficiency. Coronary artery bypass grafting (CABG) was carried out concomitantly in 314 cases (93.2%). Valve repair was performed in 140 patients (operative mortality rate 12.1%). The surgical risk in patients with a left ventricular ejection fraction (LVEF) of 10-30% was higher (operative mortality rate 33.3%) than in those with LVEF >30% (operative mortality rate 8.4%). Actuarial survival rates were 75.4%, 66.8% and 61.7% after 2, 5 and 7 years, respectively. Mitral valve replacement was performed in 197 patients (operative mortality rate 14.2%). The surgical risk in patients with a LVEF of 10-30% (operative mortality rate 30.3%) was greater than in those with a LVEF of >30% (operative mortality rate 11.0%).Actuarial survival rates after replacement were 78.6%, 73.4% 67.2% after 2, 5 and 7 years, respectively. RESULTS: Our initial analysis showed that, after mitral valve repair, mortality during follow up was greater in patients with residual mitral valve insufficiency of more than grade I. Subsequent outcome was superior when repair was evaluated perioperatively with transesophageal echocardiography. When mitral insufficiency was persistently more than grade I after repair, mitral replacement was performed. A total of 105 patients was analyzed with no or maximum grade I mitral insufficiency following valve repair; actuarial survival rates were 81%, 78.4% and 77.2% after 2, 5 and 7 years' follow up. CONCLUSIONS: Patients with highly impaired LV function and ischemic mitral insufficiency are at high risk during valve repair or replacement, and cardiac transplantation should be considered for this group. However, patients with ischemic mitral insufficiency and moderately impaired LV function can undergo valve repair or replacement with an acceptable prognosis. The goal of mitral valve repair should be to reduce valvular insufficiency to at least grade I. If this is not the case, then the prognosis of repair is worse than after valve replacement. Thus, the surgeon should replace the valve during the same operation.

Annular stabilization in mitral repair without a prosthetic ring.

BACKGROUND AND AIM OF THE STUDY: Annular stability is not guaranteed after mitral repair without a prosthetic ring. We introduce a newly developed plication technique and detail its stabilizing effect on the mitral annulus after Gerbode plasty. METHODS: Patients suffered degenerative mitral valve prolapse with chordal rupture restricted to the middle scallop of the posterior leaflet. Between 1986 and 1997, 102 patients underwent Gerbode plasty with or without annular reinforcement with a pericardial strip or modified Paneth plasty (group C). The mean (+/- SD) follow up was 70.4 +/- 41.1 months. Since 1996, 32 patients have undergone a newly developed annuloplasty technique (group N), where a pericardial strip was tightly anchored to the bilateral trigones and posterior annulus, which was folded by Gerbode plasty. With the final anchoring suture the intention was to prevent plication breakdown of this portion. Mean follow up for this group was 17.6 +/- 7.1 months. Progression of mitral regurgitation after surgery in both groups was studied. RESULTS: In group C, postoperative progression of mitral valve regurgitation occurred in 41.1% of patients (5.9% to grade 1, 17.6% to grade 2, 17.6% to grade 3). Among these patients, reoperation was due to plication breakdown of the Gerbode plasty in six cases (5.9%), and to either chordal rupture or annular dilatation in 10 cases each (9.8%). In contrast, no reoperation due to recurrent severe mitral regurgitation was needed in group N. Progression of mitral regurgitation after surgery was seen in six patients (two to grade 1; four to grade 2). CONCLUSION: The newly developed annuloplasty technique may be useful in stabilizing the mitral annulus after Gerbode plasty.

Mitral annular function assessed by 3D imaging for mitral valve surgery.

We developed a surgical technique for mitral valve reconstruction without a prosthetic ring. This procedure may have two advantages. One is avoidance of the potential thrombogenicity of the prosthetic ring, and the other is that this procedure may maintain the normal function of mitral annulus. To clarify the latter advantage, we defined a method for 3D assessment of the heart, especially for the dynamic changes of the mitral annulus. 3D images of the heart, including both mitral and tricuspid annuli in eight phases during the cardiac cycle, were reconstructed from magnetic resonance images of seven normal subjects, and used for this study. To depict the changes in the annular shape, we determined the following parameters of the annular function: (a) annular excursion, (b) direction of motion (direction cosine) and (c) orientation of the annulus (direction cosine) for the annular motion, (d) annular area and (e) displacement of the anterior portion from the approximated plane of the annulus. The data for the systolic annular motion indicate that the mitral annulus moves towards the apex with slight caudal deviation, with the excursion of 12.1 mm. The change in annular orientation indicates that the mitral annulus shows translational motion during systole. The mitral area was reduced by 25.6% (n = 5) from mid-diastole to mid-or late systole. Displacement at the anterior portion of the annulus did not change markedly during systole. The results demonstrate the physiologic function of the mitral annulus in normal subjects. This method will be applied to the clinical study of mitral valve reconstruction surgery. Based on the differences in annular length in intact and excised states, we describe the intact state of the posterior leaflet as "natural redundancy." Restoration of this natural redundancy has been a hallmark of successful mitral repair for over 20 years.

Preservation of papillary muscles and chordae during mitral valve replacement: possibilities and limitations.

The various techniques of preserving the chordal apparatus in mitral valve replacement applied in 1,453 cases at a single institution between 1986 and 1994 are described. The techniques include preservation of chordal attachment to the posterior mitral leaflet only and to both leaflets with five different technical variations. The specific advantages and risks of these techniques are demonstrated and discussed. It is concluded, that preservation of the entire subvalvular structures is feasible in almost all cases. Different procedures should be employed according to the variety of mitral disease, in particular with respect to mitral leaflet mobility.

Freehand subcoronary aortic valve and aortic root replacement with cryopreserved homografts: intermediate term results.

BACKGROUND AND AIMS OF THE STUDY: The traditional method of aortic valve replacement with a homograft has been free-hand insertion in the subcoronary position. Recently, total root replacement has become increasingly popular. We present our experiences with both methods in this study. MATERIAL AND METHODS: Between January 1, 1987 and March 31, 1996, 208 patients underwent homograft replacement of the aortic valve (free-hand subcoronary technique, n = 147 and root replacement, n = 61). The age of the patients ranged between 1.5 and 78 years with a mean age of 41 years. There were 55 females and 153 males. Ninety-four patients had infected aortic root (with 47 ring abscesses) and 114 patients had sterile aortic roots. In these series, patients with small aortic root, complicated endocarditis, dilated aortic annulus and aneurysm received aortic root replacement. RESULTS: The hospital mortality of patients with non-infected and infected roots was 2.6% and 8.5% respectively making an overall hospital mortality of 5.2%. In patients with free-hand subcoronary valve implantation (AVR) and root replacement (ARR) techniques the hospital mortality was 3.4% and 9.8% respectively. The major risk factor for death was New York Heart Association functional class IV with sepsis. Eight years patient survival in patients with AVR and ARR was 95% +/- 2% and 86% +/- 4% respectively. Freedom from structural deterioration in patients with AVR and ARR was 96.5% +/- 2% and 98% +/- 3% whereas freedom from reoperation was identical 94% +/- 2% and 93% +/- 4% respectively. However, the incidence of reoperation in patients under 40 years of age, particularly in children (< 16 years of age) during the eight years' follow up was 27%. The rate of recurrent endocarditis was 3.6% in ARR patients and development of postoperative pseudoaneurysm formation occurred in 1.4% of AVR patients with endocarditis. CONCLUSION: In conclusion, ARR technique provides low rate of reoperation in the early postoperative period. Cryopreserved homografts in the subcoronary position in adult patients < 40 years of age showed excellent medium term durability and hemodynamic performance providing evidence that long term outcome with a meticulous subcoronary implantation technique is comparable to that with the ARR technique.

Geometric mismatch between homograft (allograft) and native aortic root: a 14-year clinical experience.

OBJECTIVES: We evaluated the effect of homograft/native aortic root geometric matching and mismatching on valve survival and myocardial remodeling. METHODS: Between January 1, 1987 and March 2000, a total of 292 patients, aged 1.5-78 years (mean, 46.2 years), underwent freehand subcoronary aortic valve (AVR; n=207) and root (ARR; n=85) replacement with matched and mismatched cryopreserved homografts. All patients had pre- and postoperative two-dimensional Doppler echocardiographic studies. Two-hundred and forty-three survivors, excluding children with complete data on sizing, were followed at a total follow-up time of 1269 patient-years. Seventy percent received matched and 30% received mismatched aortic homografts. The homograft valve sizes ranged from 19 to 28 mm. RESULTS: Hospital death for elective first operation was 2.3%, and late death after a mean follow-up of 52 months was 7.9%. The patient survival at 14 years was 92+/-2%. By linear regression analysis, matched homografts were equal to or 1-2 mm less than the native aortic annulus (r(2)=0.73). The valve survival in patients with AVR and ARR was 72+/-4 and 80+/-8% at 14 years, respectively. The freedom from reoperation was 92+/-5, 77+/-4 and 48+/-10% at 14 years for matched, oversized and undersized homografts, respectively (P=0.001). The postoperative cardiac index of patients with 22 and 24 mm homografts was 3.8-4.1 l/m(2), and there was a regression of the left ventricular mass and end-diastolic diameter (P=0.001). CONCLUSIONS: The aortic homograft offers an excellent long-term clinical result. A mismatched homograft is a risk factor for postoperative aortic incompetence, reinfection with pseudoaneurysmal formation and reoperation for the freehand subcoronary implantation technique during the first 7 years of the postoperative period. It is prudent therefore to avoid mismatched homografts and use rather a properly sized stentless xenograft if a root replacement is not indicated.

Surgical management of acute aortic root endocarditis with viable homograft: 13-year experience.

OBJECTIVE: Cryopreserved homograft valves have been used for acute infective aortic root endocarditis with great success but it is compounded by its availability in all sizes. The long-term clinical results of geometric mismatched homografts are not well defined and addressed. METHODS: Over a 15-year period (April 1986-June 2001), 816 patients presented with active infective endocarditis. One hundred and eighty-two of the patients aged between 9 and 78 years (mean: 51.0 +/- 1.13 years) consisting of 142 males and 40 females received homograft aortic valves. One hundred and ten patients were in NYHA functional class III and 72 in class IV and in cardiogenic shock. Of the patients, 2.7% suffered from septic embolism. One hundred and twenty-four (68.1%) patients presented with periannular abscesses and 58 (31.9%) with no abscess while 107 native valve (NVE) and 75 prosthetic valve (PVE) endocarditis were diagnosed preoperatively by transesophageal echocardiography (TEE) and confirmed intraoperatively. Freehand subcoronary implantation (FSCI) was used in 106 patients and root replacement in 76 patients. RESULTS: The operative death was 8.5% and for patients in NYHA functional class IV and in cardiogenic shock was 14.5%. Late mortality rate was 7.9%. Patient survival after discharge from hospital at 1 year was 97% and at 10 years was 91%, respectively. Thirty-one (22.1%) patients underwent reoperation after 1.7 years (mean) with two deaths (6.4%). Early (< or = 60 days) and late reinfection rate was 2.7 and 3.6%, respectively. Freedom from reoperation for matched and undersized homografts at 10-13 years was 85 and 55%, respectively. The univariate model identified undersized homograft (P=0.002), FSCI (P=0.09) and reinfection (P=0.0001) as independent risk factors for developing early and late valve dysfunction resulting in reoperation and homograft explant. CONCLUSION: Early aggressive valve replacement with homograft for active infective aortic root endocarditis with periannular abscesses is more successful than delayed last resort surgery. Homografts exhibit excellent clinical performance and durability with a low rate of reinfection, if properly inserted. Undersized homograft is an incremental risk factor for early and late reoperation.

Tricuspid valve dysfunction and surgery after orthotopic cardiac transplantation.

OBJECTIVE: The study examines the prevalence of tricuspid regurgitation and biopsy-induced flail tricuspid leaflets after orthotopic heart transplantation and evaluates the results of the tricuspid valve surgery. METHODS: By a computerized search of the databases 647 of 889 patients who survived heart transplantation for more than 30 days were identified for this study. The primary tool for rejection monitoring in our institution is the daily observation of intramyocardial ECG (IMEG) based on day-by-day changes of the maximal QRS complex amplitude. Endomyocardial biopsy with 45-cm-long sheath bioptome was performed only in doubtful IMEG and echocardiographic data and at times of annual routine heart catheterization. Tricuspid regurgitation was diagnosed clinically and by echocardiography as mild, moderate and severe. Eleven patients received prosthetic valve replacements (four bioprostheses and seven mechanical valves) and six patients underwent valve reconstruction. The choice of xenograft valve was dictated by the condition of renal function. Patient survival and incidence of tricuspid regurgitation and freedom from operation for severe tricuspid regurgitation were analyzed with Kaplan-Meier method. RESULTS: The prevalence of tricuspid regurgitation was 20.1%. Mild and moderate tricuspid regurgitation was seen in 14.5 and 3.1% of the patients, respectively, who were responsive to medical therapy and remained clinically stable in NYHA class I-II. Severe tricuspid regurgitation was seen in 16 (2.5%) patients who presented signs of an acute right heart dysfunction. Tricuspid valve pathology at operation revealed biopsy-induced rupture of the Chordae tendineae at various valve segments mostly the anterior and posterior leaflets. There was one hospital death (<30 day) and five late deaths due to infection, arrhythmia and trauma and no procedural-related or directly cardiac related death. Ten patients (62.5%) are alive at a mean follow-up time of 29.9 months (range 4-81 months) and nine survivors are in NYHA class I-II and one in class III. CONCLUSIONS: Severe tricuspid regurgitation in transplanted hearts is associated mainly with biopsy-induced injury or endocarditis. Other regimes of rejection monitoring may help to eliminate this complication. Apart from our preference of valve repair, the choice of valve substitute may be influenced by the presence or the prospect of chronic renal failure. Heart transplant patients can safely undergo valve surgery with acceptable mortality, low morbidity and excellent intermediate-term clinical results. Mild to moderate functional tricuspid regurgitation is responsive to medical therapy and non-progressive and occur in 17.6% of orthotopic transplanted hearts without having a detrimental effect on the right ventricular performance.

Effects of prosthetic valve placement on mitral annular dynamics and the left ventricular base.

Insertion of a rigid mitral prosthesis impairs the function of the mitral annulus and induces systolic narrowing of the left ventricular outflow tract (LVOT). To study this mechanism, we investigated dynamic changes in the left ventricular (LV) base, which consists of the mitral annulus and LVOT orifice. In seven patients with mechanical mitral valve prostheses and eight normal subjects, the image of the LV base was reconstructed three-dimensionally and its dynamic change during systole was studied. In the patients, the rigid prosthetic valve (=mitral annulus) tilted toward the left ventricle with a hinge point at the posterior mitral annulus during systole. The left ventricular base exhibited contraction, but the size of the prosthetic valve was constant. As a consequence, the prosthetic valve occupied more of the left ventricular base, which resulted in narrowing of the LVOT. In the normal subjects, the mitral annulus did not interfere with the region of the LVOT orifice during systole as the mitral annulus underwent both dorsiflexion and contraction. Thus, fixation of the mitral annulus induces an anti-physiologic motion of the annulus. Conscious preservation of annular flexibility in mitral valve surgery is important in avoiding potential dynamic LVOT obstruction.

The relationship between the mitral annulus and left ventricular outflow tract.

Mitral annular inflexibility due to rigid prostheses (ring or valve) has long been considered to contribute to the mechanism of dynamic left ventricular outflow tract (LVOT) obstruction after mitral repair or replacement. In clarifying the geometric relationship between LVOT orifice and mitral valve annulus (MVA) in eight normal subjects, the authors have endeavored to show how that a rigid mitral prosthesis might obstruct the LVOT based on the assumption that any rigid prosthesis necessarily follows the motion of the posterior half of the MVA (MVApost) in the course of every heart beat. During systole, the relationship between the MVApost and the approximated plane of the LVOT orifice was constant. However, with the respect to the relationship between the LVOT orifice and the approximated plane of the MVApost (PI-MVApost), the intersection between the two shifted toward the apex during systole. Assuming the prosthesis is aligned on the MVApost with the same orientation as the PI-MvApost, this shift implies a reduction in the effective size of the LVOT orifice due to the prosthesis. The calculated obstruction rate was 24.9% (0 ms), 30.9% (100 ms), 35.5% (200 ms), and 45.4% (300 ms). These results indicate the importance of maintaining the flexibility of the MVA after mitral valve surgery.

Dynamic change in the left ventricular base with or without a rigid mitral valve prosthesis.

To evaluate the narrowing of the left ventricular outflow tract (LVOT) during systole caused by a rigid mitral prosthesis, the geometric relationship between the prosthesis (or the mitral annulus) and the left ventricular base (LVB) was studied in five patients with mechanical mitral valve prostheses and eight normal subjects. The images of the mitral valve annulus (MVA) and the LVOT orifice reconstructed in three dimensions were projected on the plane of the LV base. Calculating the areas of these projected images (i.e., those for MVA [Sm], LVOT orifice [So], the LVB [Sb; Sb = Sm + So]), the MVA-LVB ratio (Sm/Sb) was determined. In the normal subject, the MVA-LVB ratio was nearly constant during systole (59 +/- 5% at 0 msec and 62 +/- 7% at 300 msec, respectively), whereas in the patients with prostheses, the ratio increased from 61 +/- 4% (0 msec) to 69 +/- 4% (300 msec). The increase in MVA-LVB ratio reduces the proportionate share of LVOT orifice in relation to the total LVB. The ideal mitral valve prosthesis should be flexible at the annulus to attain good performance in LVB dynamics.

The inflexible mitral annulus after valve prosthesis. Inherent risk of dynamic left ventricular outflow tract obstruction.

Although chordal preserving mitral valve replacement is beneficial to cardiac function, the loss of flexibility of the annulus and consequent translational motion of the valve prosthesis during systole may cause potential left ventricular outflow tract (LVOT) obstruction after surgery. The extent of the flexibility of the mitral valve annulus (MVA) necessary for the prosthetic valve to prevent potential LVOT obstruction was determined. The three dimensional images of the MVA at 0, 100, 200, and 300 msec delay from the electrocardiogram R wave were reconstructed from cine-mode magnetic resonance images in eight normal subjects. In the lateral view of the MVA, the dorsal flexion angle (DFA) was defined. This angle implies the extent of the flexion of the anterior half of the MVA in relation to the posterior half. The data (mean +/- SD) for the DFA were 31.7 +/- 5.4 degrees (0 msec), 36.4 +/- 4.5 degrees (100 msec), 39.0 +/- 3.8 degrees (200 msec), and 43.6 +/- 2.6 degrees (300 msec), whereas the systolic increase in DFA was 11.9 +/- 3.2 degrees. The flexibility observed in normal mitral annuli is relevant to prosthetic mitral valves.