Impact of Surgical Techniques on Long-Term Results after Heart Transplantation

Despite significant limitations, which are due to the shortage of donor organs and the need for permanent immunosuppression, heart transplantation (HTx) remains the most effective therapy for end-stage heart disease in 2008. Today, orthotopic HTx is considered a standard surgical procedure. Many different surgical techniques of orthotopic HTx have been described in the literature, with the vast majority of publications describing the technique of Lower-Shumway as the gold standard. Interestingly, in 1969 a publication summarizing data from the first nine HTx procedures performed in Stanford documented that Lower and Shumway changed their surgical technique after the fourth HTx [1] according to a modification that has been described by Denton Cooley and Christiaan Barnard [2], [3] ([Fig. 1]). This modification concerns mainly the incision of the right atrium in order to protect the conduction system. Almost all consecutive HTx performed world wide applied this modification. However, the fact that the original technique has been modified in the early stage of clinical HTx is not commonly known. This might have led to reinvention of the original technique more than 40 years later [4].

Fig. 1 a and b Atrial incision of donor heart for bi-atrial anastomosis (– incision line): a Lower-Stofer-Shumway technique, b Barnard-Cooley modification. The Barnard-Cooley was introduced in order to protect the conduction system.

Heterotopic HTx techniques have been developed as a potential solution to cope with elevated pulmonary vascular resistance (PVR) as evident in patients with pulmonary hypertension. However, certain anatomic situations may preclude this option. Furthermore, the results of heterotopic HTx have been inferior to orthotopic HTx. A Kaplan-Meier survival analysis of heterotopic vs. orthotopic HTx showed that 30-day survival was 76 % vs. 87 %. By 1 year, this was 59 % vs. 74 %. At 3 years, the comparison was 56 % vs. 69 %. Repeating this analysis after subdividing the heterotopic group into those size-matched vs. size-mismatched, the 1-year survival was 81 % vs. 45 %, respectively (p = 0.02) [5]. This clearly shows that size-matching is important not only in orthotopic HTx, but as well in heterotopic HTx.

In children, moderately elevated PVR may be overcome with an oversized donor heart. Among 48 consecutive patients with pretransplant PVR greater than 4 Wood units, 38 patients underwent orthotopic HTx, and the remaining 10 received a graft in a heterotopic position. The incidence of early graft failure was similar between the groups, but heterotopic heart recipients frequently developed pulmonary complications and infection, resulting in a 30 % hospital survival in contrast to 71 % in orthotopic heart recipients (p < 0.05). The results suggest that transplant candidates with pulmonary hypertension might better be treated by orthotopic HTx with an oversized orthotopic donor heart than by heterotopic HTx [6].

As mentioned above, the biatrial technique by Cooley and Barnard modified Lower, Stofer, Shumway technique has been the standard technique used for orthotopic HTx. Since this technique of orthotopic HTx implies large atrial anastomoses which do not preserve the anatomical integrity of the donor atria, the bicaval anastomosis technique was developed in the early 1990s preserving the right atrium of the donated heart intact [7], [8]. Postoperatively, less arrhythmias and a lower incidence of tricuspid insufficiency were observed [7]. Furthermore, an alternative technique of total orthotopic HTx with complete excision of the recipient's atria was described with separate left and right pulmonary vein and bicaval anastomosis [9].

Data from the UNOS registry indicate an increasing use of the bicaval technique in orthotopic HTx in the recent era [10]. However, there was no significant difference between bicaval and biatrial technique when comparing the impact of both techniques on mid-term survival (p = 0.17). Five-year survival rates were 75 % and 72 %, respectively. A recently published meta-analysis comparing both techniques by evaluating their impact on perioperative mortality, sinus rhythm and tricuspid regurgitation provides evidence of clinically relevant beneficial effects of the bicaval technique in comparison with those of the standard technique. Nevertheless, the longer-term beneficial effects of the bicaval technique remain to be evaluated [11].

Tricuspid regurgitation (TR) is the most common valvular abnormality after orthotopic HTx with a reported incidence of up to 98 % depending on the definition of significant regurgitation and surgical methods of orthotopic HTx employed. Multifactorial causes accounting for this issue include implantation techniques, endocardial biopsies, allograft dysfunction with right ventricular dysfunction and pulmonary hypertension.

We hypothesized that right atrial geometry (surgical implantation technique) is a major determinant of post-transplant valve regurgitation and conducted a study in 166 patients who underwent HTx using standard biatrial anastomosis technique to investigate the mechanism of TR development. Echocardiography assessments and MSCT scans were performed. The study demonstrated that right atrial geometry is a major determinant of post-transplant TR. Preservation of long recipient RA anterior wall segments (D/R < 1) and abundant lateral donor atrial length in comparison to the septal length was found to be essential for its prevention. Moreover, the development of clinically relevant tricuspid valve dysfunction after optimal surgical implantation is rare and therefore does not present an limiting factor for the use of biatrial implantation technique [12].

The use of a modified inferior vena caval anastomosis has recently been described as a simple and safe technique to eliminate moderate and severe tricuspid valve regurgitation without routine annuloplasty after orthotopic HTx via the bicaval technique [13]. If tricuspid regurgitation causes significant symptoms, tricuspid valve repair or replacement is often required. As tricuspid valve regurgitation may affect postoperative outcomes after HTx, Jeevanandam and coworkers evaluated the effects of prophylactic tricuspid valve annuloplasty (TVA) during orthotopic HTx on long-term survival, renal function, and amount of tricuspid regurgitation. 60 patients randomly received either standard bicaval orthotopic HTx (group STD; n = 30) or bicaval orthotopic HTx with DeVega TVA (group TVA; n = 30) [14]. Although there was a perioperative mortality advantage in group TVA, there was no difference between groups in long-term survival. At the end of the study, however, there was a statistical difference (group STD versus group TVA, p < 0.05) with regard to cardiac mortality, average amount of tricuspid regurgitation percentage of patients with 2+ or greater tricuspid regurgitation, serum creatinine and difference in serum creatinine over baseline.

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