Left ventricle to aorta valved conduit for relief of diffuse left ventricular outflow tract obstruction.

Operative relief of congenital tunnel subaortic stenosis by means of local incision or excision, or both, has generally been unsatisfactory. The use of a valve-bearing conduit between the left ventricular apex and thoracic aorta offers a predictable means of bypassing the left ventricular outflow obstruction. The procedure was used in a 17 year old girl with an excellent hemodynamic result. The history of operative management with diverting plantation of valved conduits in this position have not been defined, but use of these prostheses appears advisable in severe subvalvular, valvular and supravalvular obstructions that are not readily amenable to predictable and safe surgical palliation. The operation may prove useful in selected cases of idiopathic hypertrophic obstructive cardiomyopathy.

Long-term follow-up of isolated replacement of the aortic or mitral valve with the Starr-Edwards prosthesis.

Review of 1,684 cases of isolated aortic or mitral valve replacement with a Starr-Edwards prosthesis demonstrated that the procedure provides improved life expectancy over that found in the natural history of valvular heart disease. Further improvement in results depends on continued reduction in operative and late mortality and in the incidence of thromboembolism. Advanced preoperative functional class, atrial or ventricular enlargement, a history of prior heart surgery, advanced age at operation and untreated valvular disease were among the factors related to increased early or late mortality. The data suggest that adequate anticoagulation, earlier performance of valve replacement and more complete repair of valvular dysfunction may increase survival rates.

Ball valve prostheses: current appraisal of late results.

Advanced actuarial techniques are used to analyze late results in 912 patients who had isolated mitral or aortic valve replacement with ball valve prostheses from 1965 to 1974. Experience with noncloth-covered and cloth-covered valves is compared in terms of late survival, rate of thromboembolic complications and reoperation and the influence of anticoagulation. The cloth-covered prostheses have substantially reduced the incidence of emboli after mitral valve replacement (1.9 vs. 6 emboli per 100 patient years) and have thus far eliminated emboli after aortic valve replacement in patients receiving warfarin. Patients with a cloth-covered aortic valve who did not receive warfarin had nine emboli per 100 patient years. The safety of cloth-covered valves is clearly enhanced by warfarin therapy; the efficacy of anti-platelet drugs is still uncertain. Strut cloth wear was found at reoperation in 10 patients. This should be prevented in the new model 2400 composite strut ("track") valve by a narrow metal track on the inner surface of each strut. The substantial recent reductions in operative mortality and in prosthesis-related complications pose important questions regarding timing of operations and selection of prostheses. These decisions must be individualized for each patient on the basis of a thorough analysis of late results using modern statistical methods.

The experimental relationship between leaflet clearance and orientation of the St. Jude Medical valve in the mitral position.

The optimal orientation of the St. Jude Medical mechanical prosthesis in the mitral position has not yet been determined. While in the majority of cases the valve can perform satisfactorily regardless of valve orientation, certain circumstances can increase the risk of leaflet impingement. These valves are commonly implanted with their leaflets oriented parallel to the anatomic axis of the native leaflets (anatomic orientation) or with their prosthetic leaflets perpendicular to the axis of the native leaflets (antianatomic orientation). To determine the influence of valve orientation on the clearance from the prosthetic leaflet to the posterior ventricular wall, we calculated the clearances on all available models of the St. Jude Medical mitral valve. Clearances were computed from measurements of valve dimensions with use of an electronic caliper. In all cases the clearance in antianatomic orientation was at least 49.5% greater (mean 59%, range 49.5% to 77.5%) than in anatomic orientation.

Bilateral enlargement of the aortic valve ring for valve replacement in children. New operative technique.

We report a new technique for the bilateral enlargement of a small aortic anulus in two children by the insertion of a bifurcated teardrop-shaped Dacron fabric lined with a porcine pericardium. Our experience in two children indicates that this technique will permit the insertion of a prosthetic valve that is four sizes larger than that measured with the native anulus intact in children weighing around 15 kg. It entails no risk of distorting the mitral valve, damaging the conduction system, the main coronary arteries or their important trunks, or of leading to left ventricular dysfunction.

Optimal delivery of cardioplegic solution for "redo" operations.

Increasing experience suggests that retrograde cardioplegia offers several benefits during cardiac reoperations. However, the need for dissection to allow caval snares for open coronary sinus intubation or to palpate the atrioventricular groove for transatrial coronary sinus intubation may disturb diseased vein grafts or require more dissection than necessary. Although antegrade-retrograde techniques can be used, antegrade cardioplegia risks atheromatous embolization from old vein grafts. To optimize delivery of cardioplegic solution, we designed and used "no touch" transatrial intubation of the coronary sinus for retrograde delivery of cardioplegic solution in 63 consecutive patients aged 20 to 87 years (mean 68 years) undergoing 36 redo coronary bypass operations, 7 combined redo coronary bypass/valve replacements, 6 redo aortic valve repairs/replacements, 6 redo mitral valve repairs/replacements, 4 redo double valve repairs/replacements, 2 redo triple valve repairs/replacements, and 2 redo composite aortic valve and arch replacements. "No touch" coronary sinus cannulation was achieved by minimally dissecting the aorta and high right atrium enough for two purse-string sutures. No attempt was made to dissect the junction of the inferior vena cava and atrioventricular groove if old vein grafts were present. The distal pressure line of the Gundry DLP RCSP retrograde cardioplegia cannula (DPL, Inc., Grand Rapids, Mich.) was connected to a transducer, flushed, and then introduced into the right atrium. The pressure tracing thus obtained was observed while the catheter was advanced, using its curved stylet, "blindly" without touching the heart, through the right atrium into the coronary sinus until a coronary sinus waveform was obtained (similar to floating a thermodilution catheter). The catheter's distal balloon was then inflated to occlude the coronary sinus momentarily. A rise in sinus pressure confirmed placement. If pressure did not rise, the cannula was usually in the right ventricle and was repositioned. All coronary sinuses were successfully intubated blindly. Bypass was then instituted, the aorta crossclamped, and the proximal aorta vented. Old vein grafts were cut at the aorta before retrograde cardioplegia was begun; atheromatous material was routinely flushed retrogradely from vein grafts. Only after arrest were hearts dissected as needed. Antegrade cardioplegia was not used. There were two (3%) deaths, both from hospital-acquired pneumonia, no perioperative myocardial infarctions, and no episodes of heart block. Inotropic agents were used in six of 63 patients (10%). We conclude that "no touch" transatrial retrograde cardioplegia offers optimal, simplified myocardial protection for cardiac reoperations, permits arrest of the heart before cardiac manipulations, and expands the use of retrograde cardioplegia by obviating cardiac dissection.

Minimally invasive mitral valve replacement: port-access technique, feasibility, and myocardial functional preservation.

OBJECTIVE: This experiment examined the feasibility of minimally invasive port-access mitral valve replacement via a 2.5 cm incision. METHODS: The study evaluated valvular performance and myocardial functional recovery in six mongrel dogs after port-access mitral valve replacement with a St. Jude Medical prosthesis (St. Jude Medical, Inc., St. Paul, Minn.). Femoro-femoral cardiopulmonary bypass and a balloon catheter system for myocardial protection with cardioplegic arrest (Heartport, Inc., Redwood City, Calif.) were used. The mitral valve was replaced through a 2.5 cm port in the left side of the chest, and the animals were weaned from bypass. Cardiac function was measured before and at 30 and 60 minutes after bypass. Left ventricular pressure and electrical conductance volume were used to calculate changes in load-independent indexes of ventricular function. RESULTS: Each procedure was successfully completed. Recovery of left ventricular function was excellent at 30 and 60 minutes after bypass compared with the prebypass values for elastance (30 minutes = 4.04 +/- 0.97 and 60 minutes = 4.27 +/- 0.57 vs prebypass = 4.45 +/- 0.96; p = 0.51) and for preload recruitable stroke work (30 minutes = 76.23 +/- 4.80 and 60 minutes = 71.21 +/- 2.99 vs prebypass = 71.23 +/- 3.75; p = 0.45). Preload recruitable work area remained at 96% and 85% of baseline at 30 and 60 minutes (p = not significant). In addition, transesophageal echocardiography demonstrated normal prosthetic valve function, as well as normal regional and global ventricular wall motion. Autopsy revealed secure annular-sewing apposition and normal leaflet motion. CONCLUSIONS: These results suggest that minimally invasive mitral valve replacement using percutaneous cardiopulmonary bypass with cardioplegic arrest is technically reproducible, achieves normal valve placement, and results in complete cardiac functional recovery. Minimally invasive mitral valve replacement is now feasible, and clinical trials are indicated.

Surgical management of the small aortic annulus. Hemodynamic evaluation.

Replacement of the aortic valve can be accomplished with ease and safety in most instances. The presence of a small aortic root, however, remains a problem in that both mechanical and stent-mounted tissue valves produce higher resting gradients in the smaller sizes. To avoid this, a technique has been developed to enlarge the aortic annulus. In a series of 253 patients undergoing aortic valve replacement, 22 required division of the aortic annulus. Extension of the incision inferiorly to the anterior leaflet of the mitral valve and a resulting separation of the annulus facilitated implantation of a larger valve. The resulting defect is obliterated with a woven Dacron patch. Hemodynamic data obtained on 12 patients who had recatheterization one to ten months postoperatively disclosed an average resting transvalvular gradient of 13.5 mm Hg. This procedure has been used successfully in combined aortic and mitral valve replacement and heart block has not occurred. Based upon encouraging follow-up studies of the Hancock glutaraldehyde-stabilized porcine heterograft, we use this prosthesis in patients with annular diameters of less than 25 mm. Our experience suggests that enlargement of the aortic annulus is necessary in a significant number of patients undergoing aortic valve replacement.

Double prosthetic aortic valve. Case report.

A 55-year-old man underwent insection of a Hufnagel valve into his descending thoracic aorta for aortic valve insufficiency 18 years ago. He remained asymptomatic for 16 years. Because of progressive left ventricular failure his incompetent aortic valve was replaced with a De Bakey carbon ball aortic valve prosthesis 2 years later. Currently, 21 months after the operation, he is doing well with two aortic valves. Review of the literature suggests that he is the first patient reported with two aortic valves functioning concomitantly and one of the longest surviving patients with a Hufnagel valve.

Section of tissue or prosthetic valve. A five-year prospective, randomized comparison.

After considerable experience, controversy persists between the selection of a tissue or prosthetic valve. In order to provide a nonbiased comparison, we designed a prospective, randomized study in September of 1970. Ninety-nine consecutive patients with isolated primary single valve replacement were randomized to tissue or prosthetic valves. The Tissue Bank supplied homografts which were either mounted for mitral replacement or used as free grafts for patients with small aortic roots. Starr-Edwards clot-covered prostheses were used for comparison. There was an even distribution of patients by age, sex, valve lesion, and New York Heart Classification attesting to the accuracy of the random selection. Anticoagulants were used in 33 patients who had operative or embolic evidence of atrial cloth or else history of thromboembolism. Thirty-five patients have undergone postoperative catheterization. Causes of death and valve failure are presented on an actuarial basis. Death in the Starr-Edwards patient group was sudden or due to fabric wear with subsequent thromboembolism, hemorrhage, or infection. We conclude that the tissue valve is a better choice for valve replacement. While there is no significant functional or hemodynamic apparent difference between the tissue and prosthetic valve, there is improvement in patient morbidity and mortality rate with the use of homografts, particularly in the aortic position. The primary cause of complications in the homograft is tissue deterioration, and this problem has been markedly reduced with advent of glutaraldehyde fixation. No such advance in solving the problem of host incompatability with the prosthesis has been forthcoming.

Improved technique of double valve replacement.

Double valve replacement in the aortic and mitral positions continues to present significant morbidity and mortality rates. At present, the replacement operation is performed with the use of either ischemic arrest or coronary perfusion. In this report, we describe a new method whereby the anterior portion of the mitral valve and the aortic valve are replaced with the aid of ischemic arrest, and then the posterior portion of the mitral valve and left atrium are repaired while the myocardium is being perfused through the native ostium. This technique has been used in 33 patients with one operative death in the last 4 years and has significantly reduced our mortality rate in this time.

Annuloplasty with flexible or rigid ring does not alter left ventricular systolic performance, energetics, or ventricular-arterial coupling in conscious, closed-chest dogs.

Eighteen dogs were randomly chosen to undergo mitral annuloplasty with either a Carpentier-Edwards rigid ring (n = 6 in each group) or a Duran-Medtronic flexible ring or to undergo a sham procedure with an operation, but no ring. Tantalum markers were inserted to measure left ventricular volume and geometry. After 1 and 6 weeks, biplane videofluoroscopic images were obtained during steady-state conditions and during vena caval occlusion. Global and regional systolic function was assessed with load-insensitive indexes. Comparison of all three groups and both times (1 and 6 weeks) showed no significant differences among the three groups in global or regional (basal, equatorial, and apical) left ventricular systolic performance. Furthermore, neither type of annuloplasty ring significantly affected left ventricular pump efficiency, ventricular-arterial coupling ratio, or systolic circumferential contraction and rotation of the basal left ventricular sites.

Mitral valve replacement through the aortic root.

This report discusses the case histories of two patients who had had previous cardiac operations and required extensive reoperations including mitral valve replacement. In both patients the replacement of the mitral valve was performed through the aortic root. This rare approach to the mitral valve, conducted with remarkable facility in these patients, encourages more liberal use of transaortic mitral valve operations in selected patients.

Partial supracoronary translocation of the aortic valve prosthesis in a case of septic destruction of the aortic root.

A patient with infective endocarditis and septic disruption of the anterior aspect of the aortic root was successfully treated by insertion of a prosthetic valve obliquely, above the right coronary ostium anteriorly and below the left posteriorly. The right coronary ostium was closed and the artery was bypassed by use of an autogenous saphenous vein graft. The procedure is considered to be an alternative to the more radical complete supracoronary translocation of the prosthetic valve, as described by Danielson and colleagues.

Universal method for insertion of unstented aortic autografts, homografts, and xenografts.

Since the advent of homograft aortic valve replacement surgery in the early 1960s, this procedure has been plagued by early aortic insufficiency. This problem has not been observed with total aortic root replacement. From September 1985 to April 1991, a modified method was used in 25 of 39 consecutive patients having aortic root replacement--seven having autografts, 30 having homografts, and two having xenografts. This technique is a new approach for implanting unstented valves in the aortic position. It decreases the probability of early failure resulting from technical malalignment of the valve during implantation. Further, it avoids the need to destroy the recipient aortic root. Whether the valve being used is an autograft, homograft, or xenograft, this method standardizes the insertion technique regardless of the anatomy or disease. Salient features of the method include the following: a longitudinal aortotomy to the aortic anulus in the midportion of the noncoronary sinus; a proximal interrupted suture line with the valve oriented in the anatomic position; and circumferential running monofilament side-to-side approximation of the donor coronary ostia to the recipient coronary ostia. The two anterior commissures are left untethered by nonclosure of the recipient aortotomy. Preliminary results have been impressive, with follow-up ranging from 1 to 3 years in 30 of these patients. Postoperative aortic insufficiency was significant in only two cases. There has been no progression of aortic insufficiency detectable by diastolic murmur or echocardiogram. Late complications have been minimal, and the overall clinical results have been excellent.

Enlargement of the aortic root or anulus with autogenous pericardial patch during aortic valve replacement. Long-term follow-up.

Patch enlargement of the aortic root or anulus is a widely accepted technique when restrictive anatomy is encountered during aortic valve replacement. Patches made of prosthetic material have been used almost exclusively, and patches of autogenous pericardium have not received wide acceptance. Although pericardium is advantageous because of its low cost, ready availability, and ease of handling, its long-term durability has not been fully established. From 1965 to 1981, 96 patients had autogenous pericardial patches placed during aortic valve replacement at the Mayo Clinic. In 81 patients, the patches were placed solely in a supravalvular position to facilitate aortic closure, while in 15 patients, the patches were placed in both subvalvular and supravalvular positions, allowing for annular expansion and insertion of a larger prosthesis. In a mean follow-up of 5.4 years, none of the 92 operative survivors has had clinical evidence of sudden patch failure and none has had patch aneurysms detected by routine chest roentgenography. One patient required reoperation for a perivalvular leak at the point where the prosthesis had been sutured to the patch. Objective data concerning the late postoperative status of the patch were available on 48 patients: 24 underwent reoperation, 16 underwent two-dimensional echocardiography, two underwent aortic root angiography, and six underwent postmortem examination. Patch aneurysms were universally absent, and in every patient the patches were well incorporated into the adjacent tissues. This proven durability suggests that autogenous pericardium is a satisfactory patch material when required during aortic valve replacement.

Valve replacement in children and adolescents.

Replacement of diseased heart valves has become the treatment of choice in many adults. Valve replacement in older children and adolescents has been done in our institution only when other procedures are ineffective. Over the past 10 years, 24 patients have received 28 artificial valves. Thirteen (54 per cent) had rheumatic heart disease; the remainder had congenital or acquired valvular abnormalities. The Björk-Shiley valve was most commonly used in the aortic position and the Beall prosthesis in the mitral position. Sixteen patients (67 per cent) survived operation and have been followed from 3 to 79 months, averaging 27 months. All are free of cardiac symptoms. Hemarthrosis occurred once in 2 survivors (13 per cent). Eight patients died (33 per cent), 5 immediately postoperatively and 3 within a year after the operation. The mortality rate has declined to 21 percent during the past 3 years. Our experience in the pediatric age group suggests that valve replacement is a serious undertaking with higher mortality rate than in adults. The operation should be reserved for those patients in whom valvuloplasty or valvulotomy is expected to be ineffective.

Results of aortoventriculoplasty in 21 consecutive patients with left ventricular outflow tract obstruction.

Results of aortoventriculoplasty (AVP) are reported in 21 patients with various types of left ventricular outflow tract obstruction (LVOTO). The concept of AVP is based on creating a surgical aortoseptal defect which is patched to provide the largest possible outflow tract to the left ventricle. Lesions consisted of isolated diffuse fibromuscular subaortic stenosis in six patients, diffuse subaortic stenosis and associated other cardiovascular anomalies in five, hypoplastic aortic anulus in two, idiopathic hypertrophic subaortic stenosis (IHSS) in two, and stenosis of a previously implanted aortic valvular prosthesis in three patients. Ten patients had had at least one unsuccessful previous surgical attempt to relieve the LVOTO. The coexisting mitral incompetence in IHSS disappeared after AVP alone. Immediate postoperative hemodynamic results were excellent in all cases. Postoperative death in five patients was due to advance myocardial failure in two, brain damage in one, transection of a dominant septal artery in one, and severe acidosis with renal failure in the last case. However, in the last 16 patients (17 operations) the only death (5.8 percent) was that caused by uncontrollable acidosis. Follow-up results indicate that 16 patients are clinically doing well, and hemodynamic studies in 14 patients are rated as excellent or good from 1 to 25 months postoperatively. It is concluded that AVP is an effective operation for managing all types of LVOTO and can be used routinely with an acceptably low mortality rate.

Aortic valve replacement with the De Bakey valve.

De Bakey prostheses were inserted in 29 patients with aortic valve disease between October, 1970, and May, 1972. Ten patients have died, but all but one of the remaining 19 have beel followed for a minimum of 19 months. Evaluation of the results in these subjects indicates that the function of the De Bakey valve compares favorably with that of other aortic valve prostheses.

Replacement of obstructed extracardiac conduits with autogenous tissue reconstructions.

Tissue-valved prosthetic extracardiac conduits fail in 6% to 30% of patients within 5 years of implantation. Failure is caused both by valve degeneration and by conduit peel formation. This report describes a technique, performed in 16 children, in which an obstructed right ventricle-to-pulmonary artery valved conduit was removed and a new conduit constructed using the conduit bed as the posterior wall and a patch of xenograft pericardium (n = 10), homograft dura mater (n = 5), or Dacron (n = 1) as the roof of the conduit. One child with pulmonary hypertension required a Björk-Shiley pulmonary valve; in the others no valve was inserted. This technique simplifies conduit replacement, allows for a generous-sized outflow tract that may grow with patient growth, and uses material unlikely to become obstructed.