Carlos M.G. Duran

Clinical and hemodynamic performance of a totally flexible prosthetic ring for atrioventricular valve reconstruction.

A new, totally flexible ring for atrioventricular annuloplasty is described. The technique for its insertion closely follows the principles of Carpentiers selective annulus reconstruction [4]. Ninety-nine such rings have been inserted (47 in the mitral and 52 in the triscuspid position); 45 valves were simultaneously replaced. There were 6 (4 hospital and 2 late) deaths. The thromboembolic incidence was 4.8%. No instances of dehiscence or late ring deterioration have been detected. Thirty-four patients have been recatheterized, 19 of them with mitral rings. The mitral gradients and angiographic findings show the correct functioning of the implanted ring. It is concluded that use of this flexible ring, which adapts to the continuous changes of the normal mitral annulus, produces a more physiological type of valve operation.

Progression of Tricuspid Regurgitation After Repaired Functional Ischemic Mitral Regurgitation

Background—Despite correction of left-sided cardiac lesions, associated functional tricuspid regurgitation (TR) that was surgically ignored can persist. It can also appear de novo. The aim of this study was to analyze TR in a group of patients who underwent successful revascularization and mitral valve repair (MVRep) for functional ischemic mitral regurgitation (MR). Methods and Results—Among 124 consecutive patients with MVRep, 70 left the operating room with MR ≤1+ and had a preoperative and follow-up transthoracic echocardiogra. Moderate or greater MR or TR was considered significant. Twenty-one patients (30%) had TR before surgery, and only 9 had TR repaired. The postoperative incidence of residual TR was not significantly different whether the tricuspid valve had been repaired (4 of 9 [44%]) or surgically ignored (8 of 12 [67%]). At last follow-up, 34 patients (49%) had significant TR. The incidence of TR increased from 25% at <1 year to 53% between 1 and 3 years and 74% at >3 years. Absence or presence of recurrent MR did not significantly affect TR (14 of 22 [64%] with MR versus 20 of 48 [42%] with no MR). Preoperative and postoperative tricuspid annulus size in patients with late TR was significantly larger than in patients without TR. Conclusions—Functional TR is frequently associated with functional ischemic MR. After MVRep, close to 50% of patients have TR. The incidence of postoperative TR increases with time. Preoperative tricuspid annulus dilation might be a predictor of late TR.

A four-dimensional study of the aortic root dynamics

OBJECTIVE Although aortic root expansion has been well studied, its deformation and physiologic relevance remain controversial. Three-dimensional (3-D) sonomicrometry (200Hz) has made time-related 4-D study possible. METHODS Fifteen sonomicrometric crystals were implanted into the aortic root of eight sheep at each base (three), commissures (three), sinuses of Valsalva (three), sinotubular junction (three), and ascending aorta (three). In this acute, open-chest model, the aortic root geometric deformations were time related to left ventricular and aortic pressures. RESULTS During the cardiac cycle, aortic root volume increased by mean+/-1 standard error of the mean (SEM) 33.7+/-2.7%, with 36.7+/-3.3% occurring prior to ejection. Expansion started during isovolumic contraction at the base and commissures followed (after a delay) by the sinotubular junction. At the same time, ascending aorta area decreased (-2.6+/-0.4%). During the first third of ejection, the aortic root reached maximal expansion followed by a slow, then late rapid decrease in volume until mid-diastole. During end-diastole, the aortic root volume re-expanded by 11.3+/-2.4%, but with different dynamics at each area level. Although the base and commissural areas re-expanded, the sinotubular junction and ascending aorta areas kept decreasing. At end-diastole, the aortic root had a truncated cone shape (base area>commissures area by 51.6+/-2.0%). During systole, the root became more cylindrical (base area>commissures area by 39.2+/-2.5%) because most of the significant changes occurred at commissural level (63.7+/-3.6%). CONCLUSION Aortic root expansion follows a precise chronology during systole and becomes more cylindrical - probably to maximize ejection. These findings might stimulate a more physiologic approach to aortic valve and aortic root surgical procedures.

Pathogenic Mechanisms in Rheumatic Carditis: Focus on Valvular Endothelium

To clarify immune-mediated mechanisms in rheumatic heart disease caused by group A streptococcal infection, valve tissues from rheumatic patients with valvular heart disease who required valve replacement were studied for reactivity with monoclonal anti-CD4 or anti-CD8 monoclonal antibodies or anti-vascular cell adhesion molecule-1 (VCAM-1). At the valve surface, CD4(+) and CD8(+) T lymphocytes were adherent to valve endothelium and penetrated through the subendothelial layer. T cell extravasation into the valve through the surface valvular endothelium appeared to be an important event in the development of rheumatic heart disease. VCAM-1 was expressed on the valvular endothelium in rheumatic valves. Evidence suggested that the pathogenesis of rheumatic heart disease involved the activation of surface valvular endothelium with the expression of VCAM-1 and the extravasation of CD4(+) and CD8(+) lymphocytes through the activated endothelium into the valve. Lymphocytic infiltration through the valve surface endothelium has not been appreciated as a potential initiating step in disease pathogenesis.

Indications and limitations of aortic valve reconstruction

To elucidate the value of conservative operation for aortic regurgitation, all consecutive patients operated on between July 1988 and July 1990 were reviewed. Of 251 patients with aortic regurgitation, 107 (42.6%) had nonprosthetic operation. The mean age was 23 years, and 90 patients (84.1%) were rheumatic. Two techniques were used: repair (annular and leaflet plasties, 69 cases) and cusp extension with glutaraldehyde-treated pericardium (25 bovine, 13 autologous). There were two hospital deaths (1.8%), both in the repair group, and no late deaths or embolic events. Only 5 patients (4.7%) were anticoagulated. In the repair group there were 12 reoperations, four (5.9%) due to aortic and eight to mitral dysfunction. In the cusp extension group there were two reoperations due to mitral dysfunction. Echocardiographic follow-up showed better results with cusp extension. In conclusion, conservative operation for aortic regurgitation is possible in a high percentage of young rheumatic patients and does not require anticoagulation. Cusp extension is more reliable than repair in terms of early results, although its long-term durability is not yet known.

The Ross procedure: current registry results

BACKGROUND The pulmonary autograft procedure for the treatment of aortic valve disease was developed and performed by Ross in 1967. The results he published in 1987 prompted increasing interest in the procedure. The International Registry of the Ross Procedure was established in 1993 to further examine longitudinal clinical outcomes. METHODS The results from the Ross registry document the continued and growing interest in the procedure with 2,523 patients currently enrolled, representing 122 centers and 166 surgeons worldwide. RESULTS Mortality (1987 to present) reported in the registry is 2.5%. It should be noted that follow-up stands at 70%. The most important issues for the registry to track are the incidence of reoperation for autograft failure and the fate of the pulmonary homograft. Reoperation for all valve-related problems is low (5.4%), with an autograft explant rate of 1.9%. Overall registry data indicate that the right ventricular outflow tract revision rate is 2.8%, with this decreasing by half to 1.3% in the 1987 to present subgroup. CONCLUSIONS Rigorous analysis of outcomes is difficult with registry follow-up currently at 70%; however, the general conclusions derived from the registry are supported by other individual series with excellent follow-up. Success of the registry depends on judicious efforts by all participating surgeons and coordinators in documenting long-term patient results and reporting them to the registry.

Analysis of the amount of tricuspid valve anular dilatation required to produce functional tricuspid regurgitation

To determine the critical anular dilatation required for functional tricuspid regurgitation (TR) and the role of systolic anular shortening in the severity of TR, 67 patients in whom right ventriculography had been performed were studied. These patients were classified into group I, control (n = 12), and the group II, patients with rheumatic valvular disease (n = 55). Group II patients were subclassified as follows: IIa, without TR (n = 19); IIb, with mild TR (n = 22); and IIc, with moderate to severe TR (n = 14). The angiographic maximal early systolic and minimal end-systolic diameters were measured. The shortening of the tricuspid anulus was expressed as percent reduction of the maximal diameter. The average maximal diameter (mm/m2) was: group I, 21 +/- 2; group IIa, 24 +/- 2; group IIb, 31 +/- 4; and group IIc, 37 +/- 4. The average minimal diameter (mm/m2) was: group I, 15 +/- 2; group IIa, 18 +/- 2; group IIb, 23 +/- 2; and group IIc, 31 +/- 3. The average percent shortening was: group I, 30 +/- 7%; group IIa, 25 +/- 7%; group IIb, 26 +/- 5%; and group IIc, 15 +/- 3%. The rheumatic patients had a larger maximal diameter than did those in the control group. Anular shortening was reduced only in the group with moderate to severe TR and preserved in the other groups, including those with mild TR. The critical diameter was determined to be between the maximal diameter in the rheumatic patients without TR and the minimal diameter in the patients with moderate to severe TR, or 27 mm/m2. Thus this easily measured parameter can determine the presence and significance of functional TR, adding objectivity to the angiographic diagnosis of TR.

Aortic valve replacement with freehand autologous pericardium

Fifty-one patients with a mean age of 31.2 years underwent aortic valve replacement with glutaraldehyde-treated autologous pericardium. Pure aortic regurgitation was present in 28 (54.9%), stenosis in 9, and mixed disease in 14. Simultaneous mitral valve repair was done in 17 patients and replacement in 1. There were no hospital and two late deaths. Three patients required reoperation because of failure of the pericardial valve as a result of infective endocarditis in two (5 and 31 months after operation) and commissural tear at 8 months in another. One patient underwent reoperation at 24 months because of failure of the mitral valve repair. The pericardial aortic valve, which had 2+ regurgitation since the first operation, was also replaced. Macroscopic and microscopic examination findings in the excised pericardium were excellent. No thromboembolic events have been detected and no patient received anticoagulation therapy except one after mitral valve reoperation and replacement with a mechanical valve. The actuarial survival was 84.53% +/- 12.29% at 60 months, freedom from failure of the aortic reconstruction 83.83% +/- 8.59%, and freedom from any event 72.59% +/- 12.79%. Doppler echocardiographic study at most recent follow-up showed a mean gradient of 12.56 +/- 8.10 mm Hg and mean regurgitation on a scale from 0 to 4+ of 0.80 +/- 0.66. Although the maximum follow-up is only 5 years, the results obtained so far encourage us to continue replacing the aortic valve with stentless autologous pericardium.

Valve Repair in Rheumatic Mitral Disease: An Unsolved Problem

Etiology plays an important role in the results of mitral valve repair. Although it is known that rheumatic disease is a negative factor, the possible influence of age has not been determined. In an attempt to study this factor, all consecutive Saudi patients operated for rheumatic mitral disease between July 1988 and December 1992 were reviewed. There were 537 patients (mean age 31.91 years). Replacement was performed in 231 patients and repair in 306. Follow‐up was 98% complete with a maximum of 52 months (mean 20 months). The patients were divlded by age into three groups: group I between 0 and 20 years (n = 145), group II between 21 and 40 years (n = 247), and group III older than 41 years (n = 145). The results showed repair rates of 76.6% (group I), 59.1% (group II), and 33.8% (group III). Actuarial survivals for repair were 95.87% (group I), 94.82% (group II), and 81.14% (group III), and for replacement were 88.33% (group I), 94.29% (group II), and 71.10% (group III). The reoperation rates for repair were 23.6% (group I), 9.6% (group II), and 8.7% (group III). There were only three reoperations in the replacement group. In conclusion: (1) the rate of repair is age dependent and inversely related; (2) repair in patients younger than 20 years of age carries a high reoperation rate; and (3) in this age group there is a higher survival tendency. (J Card Surg 1994;9[Suppl]:282–285)

Balloon coarctation angioplasty in adolescents and adults : early and intermediate results

Twenty-three adolescent and adult patients with native coarctation of the aorta underwent balloon dilatation. Dissection of the aorta developed in one patient. Data were collected on the remaining 22 patients. They ranged in age from 15 to 55 years (mean 23 +/- 9.2 years). Invasive measurement of the peak systolic gradient (PSG) and biplane angiography were performed before and immediately after angioplasty and at follow-up 4 to 48 months (mean 15 months) later. PSG before dilatation was 37 to 100 mm Hg (mean 66.9 +/- 19.9 mm Hg) and decreased to 0 to 30 mm Hg (mean 9.1 +/- 11 mm Hg) immediately after dilatation (p less than 0.001). Restenosis occurred in two patients 6 months after dilatation, and one patient had an incomplete dilatation. These three patients underwent successful redilatation and remained improved 12 to 19 months later. There was no significant change in gradient at repeat catheterization in the remaining 20 patients. PSG was 0 to 20 mm Hg (mean 5.8 +/- 7.2 mm Hg). Angiography showed that a small aneurysm developed in one patient immediately after dilatation and in another 6 months later. Eleven patients were restudied more than once, and no change in gradient or size of the aneurysm was noted at mean follow-up 25 months after dilatation. This study demonstrated that balloon angioplasty is an effective method of treating adolescent and adult patient with native coarctation of the aorta. However, because of the uncertain natural history of aneurysm after dilatation, this procedure should be considered investigational until much longer follow-up times are available.