Aortic Valve Implantation Research Articles

Allogenic heart valve bank in the Department of Cardiovascular Surgery and Transplantology of Jagiellonian University in Cracow – 23 years experience in the treatment of aortic valve or aortic root diseases.

Allogenic aortic valves are widely used in case of native aortic valve or root disease as well as failed prosthetic valves with great success. At the Department of Cardiovascular Surgery and Transplantology of the Jagiellonian University in Cracow, aortic valve or aortic root replacement with allogenic aortic valve has been performed for 23 years. Allogenic heart valve bank was founded in 1980. In the bank we prepare both aortic allografts for adult cardiac surgical procedures and pulmonary allografts that are mostly used for repair of congenital heart disease.Allogenic aortic valves implantation was usually considered in our clinic for older patients, patients with infective endocarditis of the native or prosthetic valve, young women in reproductive age and patients with Marfan syndrome. Allografts exhibit excellent clinical performance and acceptable durability with no early failure if properly inserted. Between 1980 and 1992, allografts were obtained only from cadavers during routine autopsies. More than 10% of prepared allografts were exported to other cardiac surgery centres in Poland and foreign countries. Aortic valve replacement using allogenic aortic valves can be performed with acceptable mortality and good long-term results. The procedure although surgically more challenging has the advantage of not requiring anticoagulation therapy, hemodynamic performance of the allogenic valve is excellent, it demonstrates freedom from thromboembolism and infective endocarditis. We would like to emphasize the importance and advantages of the fact that allogenic heart valve bank is placed in the department of cardiovascular surgery and it is able to supply the department in heart valve allografts 24 h a day.

The Evolving Treatment of Aortic Stenosis

The percutaneous treatment of valvular heart disease is rapidly progressing through clinical trials. For one valvular lesion, critical aortic stenosis, recent advances in technology and percutaneous techniques may potentially change the way in which we manage this disease in the most frail and elderly patients. Some of these new techniques blur the distinction between surgical and nonsurgical treatments. In this issue of Circulation , Lichtenstein and colleagues report the first series of patients to have an aortic valve implanted via a thoracotomy to expose the left ventricular apex, for subsequent sheath insertion, over-the-wire delivery system advancement, and image-guided implantation of a stent mounted equine crimped on a delivery balloon.1 This article is seminal in defining 2 major emerging issues: valvular heart disease treatments that are hybrids of surgical and catheter-based techniques and the challenges inherent in determining what treatment modalities are best in the growing problem of aortic stenosis in mature, ie, elderly, adults. This report adds to the recently published report from the St. Paul’s Hospital group in Vancouver using the retrograde percutaneous aortic valve (PAV) implantation technique.2 Article p 591 Which patients will be appropriate for these new approaches to the treatment of aortic stenosis in the mature adult population? Timely assessment of the efficacy and safety of these techniques will be critical for patients, care providers, regulatory agencies, and insurers to evaluate for patient-specific decision making and healthcare policy.

Remplacement percutané des valves sigmoïdiennes. Revue de la littérature

Surgery is no longer the only technique to replace a cardiac valve. New percutaneous procedures allow aortic or pulmonary valve implantation. Even if the feasibility of these procedures has been proved, cases reported are very rare and selected. This emergent technology is still at an early stage of development and new prospective studies will be necessary to evaluate these procedures correctly before concluding their clinical benefit. At this time surgery remains the gold standard in terms of cardiac valve replacement.

Reoperation for a patient with starr-edwards aortic valve malfunction due to pannus formation twenty-nine years after implantation

We report a re-do case of severe aortic valve stenosis due to pannus formation 29 years after an aortic Starr-Edwards caged-ball valve implantation. A huge shelf of calcified and thick pannus tissue below the valve had reduced the already small orifice by at least a third in surface area. The explanted Starr-Edwards valve revealed no mechanical or structural failure. Early detection and treatment of pannus outgrowth is essential in order to prevent life-threatening prosthetic valve malfunctions.

Reoperation after fresh homograft replacement: 23 years' experience with 655 patients.

Through a retrospective study on the use of fresh homografts in 655 aortic valve replacement patients over a period of 23 years, we aimed to assess the reasons for eventual reoperation and causes of valve dysfunction. Between January 1980 and December 2002, 655 patients received fresh homografts. All homografts were antibiotic sterilized and stored at 4 degrees C. During this time, 139 patients (116 male and 23 female) with a mean age of 46.7 years (range 18-72) required reoperation. The 30-day hospital overall mortality was 2.87%. The mean durability for all homografts was 12.4+/-4.54 years (1 month to 23 years). The cumulative rates for freedom from reoperation for any cause were 94.09+/-2% at 5 years and 87.9%+/-4% at 10 years, 76.6 at 15 years, 49.55 at 20 years. The major cause of valve dysfunction and indication for reoperation was degeneration in 111 patients (79.8%). Predominant aortic valve insufficiency in 87 patients (62.5%) and predominant stenosis in 24 patients (17.26%). Endocarditis occurred in 21 patients (15.1%). Early endocarditis was diagnosed in five patients (3.59%), late endocarditis in 16 patients (11.5%). Additional causes for reoperation included ascending aortic aneurysm, mitral valve insufficiency and congestive cardiomyopathy. Seventeen patients (12.2%) required concomitant procedures. Coronary artery bypass grafting was performed in six cases (4.3%), mitral valve replacement in five cases (3.59%), mitral valve annuloplasty in six (4.3%). The primary reoperative procedure was artificial/mechanical aortic valve implantation. In five cases, St. Jude Medical conduit grafts were implanted due to ascending aortic aneurysms. Homograft reimplantation was performed in four cases. One patient underwent mitral valve replacement and one patient received a heart transplant. The results of the study suggest that reoperation in patients with aortic homografts is a low-risk procedure as compared to alternative therapies. Primary allograft aortic valve replacement can give acceptable results for up to 23 years. The major cause of valve dysfunction and indication for reoperation was degeneration. Cumulative rates for freedom from reoperation for any cause in age groups suggest careful selection and indications in homograft implantation in the younger patients. Young age is a risk factor for an early homograft structural deterioration (degeneration).

Complex Cardiac Stab Wound

A 40-year-old man who was involved in an altercation received a stab wound to the chest, medial to the left nipple. He was brought to the emergency department at Baylor University Medical Center; immediate resuscitation was started and continued in the operating room, where continued bleeding after placement of the chest tube prompted emergency thoracotomy. A bleeding wound in the right ventricle anteriorly was found, and it was closed by sutures. Although the immediate postoperative course was uneventful, mild dyspnea appeared, a systolic precordial murmur was heard, and the chest radiograph showed an enlarged right ventricular cavity. Echocardiogram showed an enlarged right atrium and ventricle and suggested an abnormal left-to-right communication or “shunt.” A transesophageal echocardiogram confirmed a left-to-right shunt and showed an aorta-to-right-ventricular-outflow-tract fistula (Figure 1), but the exact position was indeterminate. Cardiac catheterization showed elevated right-sided cardiac pressures with a 2-to-1 left-to-right shunt (Figure 2). Still, the precise location of the shunt was not determined but was thought to be near the aortic valve or in the subvalvular region of the ventricular septum. Because of the hemodynamically significant shunt, another thoracotomy was performed. Cardiopulmonary bypass and cardiac arrest were used to stop the heart, allowing direct visualization of the injury. The stab wound had entered the right ventricular cavity, having traversed its outflow tract and penetrated the ventricular septum and the aortic tissue below the right cusp of the aortic valve. The width of the patient's stab incision was approximately 1 cm. The left-ventricular-outflow-tract-to-right-ventricular-outflow-tract injury was repaired with 2 reinforced sutures placed below the aortic valve Intraoperative transesophageal echocardiogram confirmed the completed repair of the aorta-to-right-ventricular-outflow- tract fistula. The patient's convalescence was normal. Penetrating heart injuries are often fatal (10% to 60%) (1–3) and are catalogued as either gunshot wounds or stab wounds. Gunshot wounds of the heart are generally associated with 2 to 4 times the mortality of stab wounds to the heart (2,3); this is thought to be related to the surrounding tissue injury of the highvelocity projectile vs the low velocity of the stab instrument. Because of the muscular nature of the ventricular walls, traumatic incisions and lacerations (stabs) of the left ventricular wall and, to a lesser extent, the right ventricular wall, will often temporarily seal and allow time for transport to a medical center (1,3). The thin atrial walls, in contrast, seldom seal without an external force, such as a clamp or suture. External cardiac compressions usually cause profuse bleeding with tamponade and rapid death. This present case illustrates well the optimal management of a cardiac stab wound that did not cause heart failure, dysrhythmias, or myocardial ischemia. Posttraumatic intracardiac shunt is uncommon (4), but it can result in infective endocarditis ( 2.0, the incidence of eventual failure and/or dysrhythmias is high (6). Such progression to right heart failure is variable and may take more than a decade to manifest itself. Consequently, these “low” injuries are lesions in which shunt observation for a period of time is rational. By the time normal wounds are expected to fully heal (about 8 to 12 weeks), continued presence of the shunt indicates fistulization or epithelialization of the tract, and elective surgical repair is indicated. A subvalvular ventricular septal defect may cause sagging and/or damage of 1 or more aortic valve cusps and eventually cause aortic insufficiency (7). The ventricular septal defect in the present patient could be closed via aortotomy using suture alone or patch. The reinforced suture technique was employed because of its simplicity. A patch was avoided to reduce the chance of aortic valve distortion and implantation of a foreign body. The patient's normal postoperative convalescence is a testimony to the resilience of youth as well as the diligent pursuit of unusual abnormalities in a “usual” trauma patient. Care of this patient underscores one of the most important positive attributes of Baylor University Medical Center: the close and coordinated multidisciplinary efforts of the trauma surgery, cardiology, and thoracic surgery services in difficult cases.

Mitral valvuloplasty with sutures used for aortic prosthesis implantation

Background. The purpose of this study was to analyze surgical treatment for aortic valve lesions with coexisting mitral regurgitation (MR). Methods. Seventy-five patients were divided into two groups according to intensity of MR (group 1, MR less than or equal to II; group 2, MR greater than or equal to II/III). There were two control groups (control 1, only patients with implantation of aortic valve; control 2, patients with implantation of both aortic and mitral prostheses). During implantation of a mechanical aortic prosthesis, the same suture for fixation of a mechanical prosthesis and for suspension of mitral commissural regions and lifting the base of anterior mitral cusp was used. Results. In all patients, no early death occurred. There were two late deaths, one due to endocarditis, and the other to heart failure. All patients from both groups had decreased MR. Selected echocardiographic parameters improved: end diastolic and end systolic diameter and ejection fraction in group 2 improved in proportion to patients in whom mitral valves were implanted (control 2). Conclusions. Simultaneous suspension of the mitral commissure area during mechanical aortic prosthesis implantation reduces associated MR. This technique seems to be efficient during implantation of aortic prostheses in patients with coexisting MR.

Serial Doppler Gradients Are Predictive of Future Bioprosthetic Valve Degeneration.

Doppler echocardiography and color flow imaging are helpful techniques in evaluating the functional status of a bioprosthetic valve. The aim of this study was to determine whether serial Doppler gradients are predictive of future bioprosthetic valve degeneration. We performed serial echo-Doppler studies over a 6-year period (1988-1994) on 228 patients who had undergone mitral (n = 112) or aortic (n = 116) bioprosthetic valve implantation between 1973 and 1994. Thirty-nine mitral prostheses and 30 aortic prostheses became dysfunctional and required reoperation. A serial rise in mean gradient of 5 mmHg or more across the mitral valve and 25 mmHg or more across the aortic valve was significantly associated with increased valve degeneration (odds ratio 3.40 and 16.11 and 95% confidence intervals 1.31 and 8.80 and 13.6 and 72.13 for the mitral and aortic valve, respectively). Both aortic and mitral valves began to degenerate after 8 years. Serial echo-Doppler studies showed a rise in transvalvular gradients around the same time. Closer evaluation for prosthetic valve dysfunction should be considered in patients 8 or more years status post surgery, especially those with high transvalvular gradients.

Long-Term Evaluation of Orthotopically Implanted Stentless Bioprosthetic Aortic Valves in Juvenile Sheep

The aim of this study was to develop a technically feasible and reproducible model for chronic evaluation of stentless bioprosthetic aortic valves implanted orthotopically using juvenile domestic sheep. This report summarizes the results of a study conducted to assess orthotopically placed 19-mm stentless aortic bioprosthetic valves. Twenty-seven juvenile sheep underwent aortic valve replacement. Standard cardiopulmonary bypass techniques were followed. The average cardiopulmonary bypass time was 73 min. No chronic anticoagulation was used. There were two deaths (7%) due to surgical complications. In the remaining 25 experiments, 11 animals (41%) died prior to the scheduled sacrifice on postoperative day 150. One early death occurred due to coccidiomycosis infection, one due to technical error, one due to pulmonary embolus, four due to prosthetic annular size disproportion, and four due to thrombi. The remaining 14 animals (52%) underwent left and right heart catheterization, angiography, echocardiography, and sacrifice after postoperative day 150. The average weight of the sheep at elective sacrifice was 60 kg (mean weight gain 12.5 kg). The average cardiac output for the sacrificed animals was 5.1 L/min. The mean velocity of blood across the aortic valve for the sacrificed animals was 317 cm/s and the mean pressure gradient was 26.2 mm Hg. Two features suggest that this model may have broad application. First, we have demonstrated that it is technically feasible to evaluate orthotopically placed stentless bioprosthetic aortic valves in growing sheep. Second, the aortic root size of the juvenile sheep allows for implantation and evaluation of a human size aortic valve (19 mm). We believe that this model is reproducible and can be used to study stentless valve designs.

The stentless bioprosthesis: surgical challenges and implications for long-term durability

An attempt is made to analyse the factors which are expected to influence clinical results following implantation of a stentless porcine bioprosthesis. Long experience with implantation of allograft aortic valves provides a meaningful basis for comparison with a glutaraldehyde-fixed device. Morphological differences between the two valves involve the aortic wall and muscle shelf, and differences in valve preparation include the strength and stiffness of the aorta and the extensibility of the valve leaflets. As a result of these differences, sizing of the porcine valve is expected to be more critical than the allograft valve and the porcine valve is also expected to be more obstructive. Methods for reducing the obstructive element include the use of a composite aortic valve, a porcine pulmonary valve, or a valve in which the aorta is glutaraldehyde-fixed under pressure while the leaflets are pressure-free. The techniques available for implantation, namely freehand insertion, total root replacement and mini-root replacement, are examined.

Hypothermia and circulatory arrest in reconstruction of aortic arch. A report of nine cases.

From 1982 until October 1985 we operated 9 cases of aortic aneurysm involving the transverse aortic arch (5 male and 4 female, from 26 to 69 years). Two patients had an acute dissecting aortic aneurysm, the others had an aneurysm of the aortic arch involving also the ascending aorta in 5 cases and the descending aorta in 1. Three patients underwent aortic valve replacement and implantation of coronary orifices. Two patients had previously had AVR. The operation was carried out under cardiopulmonary by-pass. After obtaining 25 degrees C hypothermia the bypass was discontinued and the cerebral vessels were cannulated from inside of the opened aneurysm and perfused at a flow rate of 250 ml/min. The myocardium was protected by cold cardioplegia and topical cooling. During total circulatory arrest the distal aortic arch anastomoses were completed in 28-56 minutes. Then the by-pass was restarted and the rest of the operation was carried out as usual. One patient with an acute dissecting aortic aneurysm died on the 2 post-operative day due to brain damage and rupture of abdominal aorta. The other patients recovered well. There were no permanent neurological or myocardial complications. Three patients had a transient renal failure, one needing dialysis. The 8 survivors have done well 4-46 months after the operation.

Results of valve replacement with the Omniscience prosthesis

Clinical experience with the Omniscience prosthesis from two regional cardiac units in England is presented. Actuarial analysis suggests a prohibitive incidence of prosthetic thrombosis of the mitral valve, this complication occurring in 14 of a total of 96 (15%) patients studied over a mean period of approximately 1 1/2 years. Aortic valve implantations were frequently complicated by prosthetic dehiscence, which occurred in nine of a total of 88 (10%) patients who received this valve. Our results with this prosthesis contrasts markedly with our favorable experience with other types of prostheses and lead us to question the suitability of the Omniscience valve for further clinical use.

THE ST JUDE MEDICAL VALVE—THE AUSTRALIAN EXPERIENCE

Since October, 1978, 181 St Jude medical cardiac valves have been implanted in 166 patients throughout Australia. There were 152 single implants, 13 combined mitral and aortic valve implants, and one triple valve implant. Hospital mortality rates were similar to those for all types of prosthetic cardiac valves. Thromboembolic complications occurred less frequently in the patients with St Jude valves than in reports of similar patients with other prostheses, provided that anticoagulation was maintained.

Arrhythmias and conduction disturbances following aortic valve implantation.

In the first postoperative week following aortic valve implantation, arrhythmias and conduction disturbances were seen in 37 of 44 patients studied. Sixty-seven episodes of arrhythmias occurred, atrial fibrillation and accelerated junctional rhythms accounted for more than 75% of these episodes. Episodes of atrial fibrillation were most common after the age of sixty.l When atrial premature contractions were observed, episodes of atrial fibrillation followed shortly afterwards. Accelerated junctional rhythms were seen in 17 patients and affected the patients haemodynamically when this dysrhythmia occurred early in the postoperative course, but improvements were seen promptly following atrial overpacing. Lidocaine was infused prophylactically for 2 days in patients with severe aortic stenosis or marked left ventricular hypertrophy. One episode of ventricular fibrillation and few incidents of ventricular extrasystoles were seen. Most conduction disturbances were transient, but bundle branch block persisted in 3 patients, and there was complete A-V block in a fourth. No causal relationship between the use of digitoxin and the frequency of arrhythmias could be established.