Charles A. Yankah

Aortic valve replacement with the Mitroflow pericardial bioprosthesis: Durability results up to 21 years

OBJECTIVE The study aim was to analyze the performance profile of a large series of Mitroflow pericardial valves (Sorin Group Canada Inc. Mitroflow Division) in the very long term. METHODS Data from 1513 patients with isolated aortic valve replacement who received pericardial bioprostheses between 1986 and 2007 were analyzed. Cumulative duration of follow-up was 6164 patient-years with a maximum duration of 21 years. Actuarial rates of valve-related events were calculated by the Kaplan-Meier method and the Cox multivariate analysis to identify independent determinants of outcome. RESULTS Hospital mortality for elective surgery was 2.5%. Late death was 40.6%. Reoperation was required in 86 (5.7%) patients and was valve related in 83: structural valve deterioration in 64 (4.2%) patients, prosthetic valve endocarditis in 17 patients (1.1%), valve thrombosis in 1, and periprosthetic leak in 1. Rates of 20-year actuarial freedom from valve-related morbidity were as follows: structural valve deterioration 84.8% (actual 96.6%) in patients 70 years of age or older; thromboembolism 94.1%; and prosthetic valve endocarditis 96.8%. Twenty-year actual risk of reoperation for structural valve deterioration was 11.4% in all patients and 3.4%, in patients 70 years or age or older. Advanced age, renal insufficiency, pulmonary disease, and low body mass index were independent risk factors for late outcome (P < .001). CONCLUSIONS After 2 decades of follow-up, the Mitroflow pericardial aortic valve continues to be a valve of choice with a predictable low rate of valve-related events, particularly for patients over the age of 65 to 70 years and others with comorbidities.

Cannulation of the right axillary artery for surgery of acute type A aortic dissection

OBJECTIVE The optimal choice of the arterial inflow site during operations for type A aortic dissection is not clearly defined. The aim of the prospective study was to identify whether cannulation of the right axillary artery instead of the femoral artery may improve the results of surgery for acute type A aortic dissection. METHODS Seventy consecutive patients were operated on because of acute type A aortic dissection from January 2000 to February 2002. The only difference in surgical strategy was the site of arterial cannulation: the right axillary artery was used in 20 patients [axillary group] and the left femoral artery in 50 patients [femoral group]. All patients had aortic surgery with open distal anastomosis during deep hypothermic arrest and retrograde cerebral perfusion. The mean age was 58.7 +/- 12 years with a range from 28 to 88 years (axillary group, 56.6 +/- 13 years; femoral group, 59.4 +/- 12 years; P = 0.435). Preoperatively evident organ malperfusion was identified in five (25%) patients of the axillary group and in seven (14%) of the femoral group. RESULTS There was no perioperative death. The hospital mortality rate was 5.0% for the axillary group and 22% for the femoral group (all patients, 17%). Major neurological complications occurred postoperatively in 5% of patients from the axillary group (one out of 20 patients) and in 8% of patients from the femoral group (four out of 50 patients) (all patients, 7%). CONCLUSION Cannulation of the right axillary artery improved the outcome of surgery for acute type A aortic dissection. However, postoperative complications occurred after both axillary and femoral artery cannulation.

Stentless aortic valves as an alternative to homografts for valve replacement in active infective endocarditis complicated by ring abscess

BACKGROUND The valve substitute of choice in active infective aortic valve endocarditis complicated by annulus abscess in our institution is the cryopreserved homograft. To avoid implantation of any prosthetic material, the Shelhigh No-React stentless valves and conduits may be considered an alternative when no suitable homograft is available. METHODS Between March 1986 and January 2001, 452 homografts were implanted in the aortic position. From January 2000 to August 2001, 75 Shelhigh No-React prostheses were implanted at our institution. In 25 consecutive patients (study group) with aortic annulus abscess, urgent aortic valve replacement with the Shelhigh SuperStentless and Stentless Aortic Valve Conduit was undertaken. Patients (16 male, 9 female; age, 49 +/- 19 years) were studied with follow-up until March 2002. The control group comprised 68 consecutive historical patients (46 male, 22 female; age, 53 +/- 14.4 years) with similar disease treated between January 1997 and December 1999 in whom an aortic homograft was implanted. This group was also followed up until March 2002. Demographic data and preoperative characteristics of the patients were without significant differences. Patients were studied by echocardiography. RESULTS Sixty-day mortality was 16% (11 patients) in the control group compared with 12% (3 patients) in the study group. Recurrent infection occurred in 4% in both groups. The instantaneous and mean Doppler gradients yielded no significant differences (19.4 +/- 10.4 mm Hg and 11.8 +/- 5.7 mm Hg versus 18.2 +/- 8.7 mm Hg and 10.9 +/- 5.3 mm Hg, respectively). The mean effective orifice area calculated from Doppler flow velocity for the stentless valve was 2.3 +/- 0.6 cm2. Preoperative evaluation of left ventricular dimensions and global left ventricular systolic function did not vary significantly between the two groups. However, postoperatively evaluated left ventricular end-diastolic diameter dimensions in the study group were significantly smaller than those in the control group (47.6 +/- 7.9 mm versus 56 +/- 9.5 mm; p = 0.05). Ejection fraction was similar in both groups (56.2% +/- 12.8% for the study [Shelhigh] and 52.6% +/- 16.8% for the control [homograft] group). CONCLUSIONS Our experience with both the Shelhigh No-React SuperStentless and Stentless Aortic Valve Conduit in patients with native or prosthetic aortic valve endocarditis appears to demonstrate good results, similar to those of cryopreserved homografts. Ease of implantation and favorable effective orifice area and pressure gradients, as well as the No-React anticalcification treatment, are promising factors.

Surgical therapy in patients with active infective endocarditis: seven-year single centre experience in a subgroup of 255 patients treated with the Shelhigh® stentless bioprosthesis

OBJECTIVE We investigated outcomes after surgical therapy in patients with active infective endocarditis (AIE) with regard to survival in relation to surgical urgency, valve position, number of valves implanted and abscess formation. We aimed to identify independent risk factors for early mortality. METHODS AND RESULTS Two hundred and fifty-five patients received Shelhigh bioprostheses between February 2000 and March 2007. A total of 74.1% had native and 25.9% prosthetic AIE. Surgery was regarded as urgent in 57.3% and as an emergency procedure in 38.4%. There was a highly significant difference in survival rate between patients who were operated on urgently versus in an emergency (p<0.0001), between single and double valve replacement (p=0.0206) and between patients with and without abscess formation (p=0.0245). There were two cases of early reinfection (0.78%) and six of late reinfection (2.35%) leading to re-operation. CONCLUSIONS The survival of patients differs significantly in dependence on their surgical urgency. Better outcome could have been achieved if patients had been referred earlier for surgery and operated upon before heart failure or septic shock developed. Long-term survival was better in patients without abscess formation. The low reinfection rate of Shelhigh bioprostheses in AIE is promising and the early and mid-term results achieved need to be verified in the long-term course.

Mitroflow aortic pericardial bioprosthesis--clinical performance.

OBJECTIVE Advancing life expectancy with the increased prevalence of aortic valve degenerative disease brings the need for an aortic bioprosthesis with excellent haemodynamic performance and comparable durability. The Mitroflow bioprosthesis has been on the worldwide market, except in the United States, since 1982, while the current model (1991) has only recently gained regulatory approval in the latter country. This study was primarily performed to determine the durability of the current Mitroflow bioprosthesis. METHODS The contemporary Mitroflow bioprosthesis was implanted in 381 patients in three centres. The mean age was 76.4 years (range 53-91 years) and the mean follow-up period was 5.4+/-3.4 years, a total of 2048.7 years of evaluation. Prosthesis-patient mismatch (PPM) was classified by reference effective orifice area index categories: normal > or = 0.85 cm(2) m(-2) (53.9%), mild 0.84-0.76 cm(2) m(-2) (33.9%), moderate < or = 0.75-0.66 cm(2) m(-2) (11.7%) and severe < or = 0.65 cm(2) m(-2) (0.5%). RESULTS The survival, at 10 years, was 39.9+/-7.9% for 50-69 years, 27.0+/-3.7% for 70-79 years and 16.6+/-4.4% for > or = 80 years (p=0.011). There was a trend (p=0.063) influencing survival for moderate-to-severe PPM. Of the independent predictors influencing survival--moderate-to-severe projected effective orifice area index (pEOAI) (Hazard Ratio (HR) 1.6, p=0.0142) and left ventricular dysfunction (ejection fraction < 35%) (HR 1.9, p=0.0193) were included. The 10-year freedom from structural valve deterioration (SVD) at explant assessing the same age groups as survival was not different (p=0.081). The 10-year actual/actuarial freedom from SVD, at explant was for > or = 60 years--94.4+/-1.4% (85.2+/-3.9%), for > or = 65 years--94.2+/-1.4% (85.0+/-4.0%), for 61-70 years--97.4+/-2.6% (95.7+/-4.3%) and for > 70 years--94.0+/-1.5% (83.2+/-4.6%). CONCLUSIONS The Mitroflow external mounted, pericardial aortic bioprosthesis with documented excellent haemodynamics (especially for the small aortic root), demonstrates that prosthesis-patient mismatch in moderate and severe categories can essentially be eliminated, with durability performance comparable to other heterograft (porcine and pericardial) bioprostheses.

Cardiac Surgery Capacity in Sub-Saharan Africa: Quo Vadis?

BACKGROUND Current data on cardiac surgery capacity on which to base effective concepts for developing sustainable cardiac surgical programs in Africa are lacking or of low quality. METHODS A questionnaire concerning cardiac surgery in Africa was sent to 29 colleagues-26 cardiac surgeons and 3 cardiologists in 16 countries. Further, data on numbers of surgeons practicing in Africa were retrieved from the Cardiothoracic Surgery Network (CTSNet). RESULTS There were 25 respondents, yielding a response rate of 86.2%. Three models emerged: the Ghanaian/German model with a senior local consultant surgeon (Model 1); surgeons visiting for a short period to perform humanitarian surgery (Model 2); and expatriate surgeons on contract to develop cardiac programs (Model 3). The 933 cardiothoracic surgeons listed by CTSNet translated into one surgeon per 1.3 million people. In North Africa, the figure was three surgeons per 1 million and in sub-Saharan Africa (SSA), one surgeon per 3.3 million people. The identified 156 cardiac surgeons represented a surgeon to population ratio of 1:5.9 million people. In SSA, the ratio was one surgeon per 14.3 million. In North Africa, it was one surgeon per 1.1 million people. Open heart operations were approximately 12 per million in Africa, 2 per million in SSA, and 92 per million people in North Africa. CONCLUSION Cardiothoracic health care delivery would worsen in SSA without the support of humanitarian surgery. Although all three models have potential for success, the Ghanaian/German model has proved to be successful in the long term and could inspire health care policy makers and senior colleagues planning to establish cardiac programs in Africa.

Heart valve operations in solid organ recipients: an 18-year single-center experience.

Background. We retrospectively analyzed the outcome of heart valve operations in solid organ recipients, who were referred for operation to our institution. Methods. Over an 18-year period, 23 heart (group 1) and 16 renal (group 2) transplant recipients in New York Heart Association (NYHA) classes III and IV underwent valve operation. The mean interval from the time of transplantation to cardiac surgery was 77.9 months with a mean follow-up time of 34.6 months in group 1 and 87.2 months with a mean follow-up time of 39.2 months in group 2. Results. Group 1 underwent tricuspid valve replacement (n=12), tricuspid valve reconstruction (n=7), aortic valve replacement (AVR, n=3), and mitral valve replacement (MVR, n=1). In group 2, mechanical valve replacement was performed in 14 patients (9 AVR, 3 MVR, 2 AVR and MVR) and tricuspid or mitral valve reconstruction in two patients. There was no operative death. During hospitalization, multiorgan failure due to sepsis was the main cause of mortality (2 in both groups). In the mean follow-up period of 41.2 months, there were four late non-cardiac-related deaths in group 1. Currently 29 surviving transplant recipients (16 heart, 69.6% and 13 renal, 81.3%) are in NYHA classes I and II. Conclusion. In heart and renal recipients, valve operations can be performed effectively and safely with acceptable mortality, low cardiac morbidity, and excellent clinical results, although infection is the most serious complication.

The aortic root

The shape of the aortic valve leaflet was first described by Philiston [1] in the 4th century BC as semilunar, and in 1513 Leonardo da Vinci [3] depicted in a drawing the geometry of the orifice of an opened and closed aortic valve as triangular and with three adjacent hemispherical forms, respectively (Figs. 1–3). Valsalva described the aortic sinuses in 1740 and suggested that the coronary artery filling takes place in the sinuses during diastole [4]. Recent echocardiographic and computed tomographic descriptions of the aortic valve and root diseases [5, 6, 7] and their relationship to the coronary artery origins have documented the importance of imaging the aortic root and the impact on the technical artistry of aortic root replacement, valve-sparing surgery, and minimally invasive transcatheter aortic valve replacement (Figs. 4–7) [8, 9, 10, 11, 12]. In fact, 2.9% of adults older than 65 years have calcific aortic stenosis [7]. Open image in new window Fig. 1. Echocardiographic imaging of the aortic root: short and long axis view. a Short axis view: severe AS: AVA 0.5 cm2; b long axis view: aortic valve annulus ∅ 24 mm; c mild mitral regurgitation, moderate tricuspid regurgitation Open image in new window Fig. 2. Cardiac computed tomographic view of the aortic root: end-systolic phase. The anatomic relationship between the aortic annulus and the coronary artery are shown Open image in new window Fig. 3. a The aortic valve in systole. b Opened leaflets in a triangular configuration. c The aortic valve in diastole in a configuration of three adjacent hemispheric form Open image in new window Fig. 4. Cardiac computed tomographic view of the aortic root. a Annulus 26 mm, b distance to left main coronary artery: 16 mm, c distance to RCA 16 mm Open image in new window Fig. 5. a The Edwards Sapien transcatheter self-expandable pericardial valve. b Transapical implantation of the Edwards Sapien self-expandable sutureless pericardial valve in the aortic root Open image in new window Fig. 6. Transapical valve-in-valve implantation of Edwards Sapien valve in a bioprosthesis after structural valve deterioration. a Introduction of the unexpanded Edwards Sapien valve into the bioprosthesis after balloon dilatation. b Implanted self-expandable Edwards Sapien valve in the bioprosthesis Open image in new window Fig. 7. Synopsis of a symptomatic aortic stenosis for transcatheter aortic valve replacement (AVA aortic valve area, STS Society of Thoracic Surgeons, TEE transesophageal echocardiography, CT computed tomography, AVR aortic valve replacement, TAVR transapical aortic valve replacement, TFAVR transfemoral aortic valve replacement)

Implantation of a left ventricular assist device in situs inversus

A 42-year-old man with situs inversus was referred to our institution because of end-stage ischemic cardiomyopathy. Cardiac arrest occurred after admission, and the patient underwent cardiopulmonary resuscitation. An extracorporeal left ventricular assist device (Berlin Heart) was implanted as a bridge to transplantation. This is one of the first reports of left ventricular assist device implantation in a patient with situs inversus and ischemic cardiomyopathy.

Aortic root abscess: reconstruction of the left ventricular outflow tract and allograft aortic valve and root replacement

Active infective aortic endocarditis complicated by abscess formation remains a life-threatening disease and continues to challenge cardiovascular surgeons. Sir William Osler first described endocarditis in the Gulstonian lectures at the Royal College of Physicians in 1885 as a malignant disease that is in all its forms a mycotic process. An aortic root abscess can be diagnosed very early at its onset by transthoracic and transesophageal echocardiography with a sensitivity and specificity of 98 and 100%, respectively [1, 2, 3]. If after diagnosis, during antibiotic therapy, associated complications occur, such as burrowing abscess formation and fistulous communication between the aorta and the right atrium or the right ventricle, interventricular septum, aneurysm of the sinus Valsalva, pseudoaneurysmal formation of an abscess cavity and mitral incompetence, then urgent surgical intervention is mandatory, otherwise fatal cardiovascular complications are imminent [1, 2, 3, 4, 5].