Measures of prevention and technical problems during reoperations in cardiac surgery

Reoperations after cardiac valve replacement are unavoidable: their frequency depends on surgical technique, type of valve used, and the anatomical situation. Erlangen, almost 300 such procedures were required among 3500 valve replacements, while 19 out of 700 bioprostheses had to be exchanged. Statistically relevant complications occurring with variable frequency are paravalvular leakage, thrombosis and degeneration of the bioprostheses which have to be corrected for hemodynamic reasons. Other indications are thromboembolism and endocarditis. Rare complications are: rupture of the posterior wall of the ventricle or aortic root with subsequent development of aneurysm, entrapment of the occluder due to long sutures, pannus, muscle chordae, strut fracture (Björk) or wear of the occluder (Wada, Starr, Edwards, Beall). Some complications as dehiscence, entrapment, rupture and aneurysm of the posterior wall of the ventricle and aortic root can largely be avoided by good surgical techniques. Reoperative mortality rate is slightly higher due to greater possibilities of injury and bleeding. Emergency procedures in grade IV NYHA have the highest rate (50%), elective procedures for leakage, calcified or regurgitant bioprostheses the lowest. The most frequent indication for re-operation is perivalvular leakage. Dehiscence requires surgery to deal with hemolysis or for hemodynamic reasons. Dehiscence is more common in aortic than in mitral position; the latter can be closed by felt-padded stitches in 80%. This technique is the most reliable in preventing leakage, although thrombosis is more likely. Causes of dehiscence are endocarditis, suture-line tearing, calcium in the annulus. The incidence of valve thrombosis is related to valve type, usually associated with inadequate or abruptly terminated anticoagulation therapy (rebound). Disc valve are at particular risk.(ABSTRACT TRUNCATED AT 250 WORDS)