CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 7, August 2013
AFRICA
251
A retrospective analysis of factors influencing re-operation
in patients undergoing mechanical valve replacement
EBUZER AYDIN, FIKRI YAPICI
Abstract
Background:
We aimed to determine the possible factors
leading to re-operation in patients undergoing mechanical
valve replacement and to investigate the relationship between
valvular thrombus formation and mean platelet volume.
Methods:
The medical records of 43 patients with mechanical
valve implantation, who were admitted to the Department of
Cardiovascular Surgery of Dr Siyami Ersek Thoracic and
Cardiovascular Surgery Training and Research Hospital
between 2000 and 2005 were analysed retrospectively. Data
recorded included demographic characteristics, valve type,
size and location, implantation position, warfarin use, INR
level, additional cardiac intervention, presence of left atrial
thrombus, valvular thrombus, pannus formation, perival-
vular leak, left atrial aneurysm, platelet count and mean
platelet volume (MPV), bleeding after the primary surgery
and/or revision of surgery due to other reasons, valve protec-
tion, aortic root expansion, presence of valve calcification
and infective endocarditis, pre- and postoperative rhythm
pattern, brand name of prosthesis, distance of the patient’s
house from a cardiac surgery centre, and concomitant non-
cardiac systemic diseases.
Results:
Mean age was 49.3 years (range 19–78 years). Of the
patients, 51% (
n
=
22) were males and 49% (
n
=
21) were
females. The re-operation mortality was 11.6%. Age, gender,
valve type, brand of valve prosthesis, and implantation posi-
tion were not risk factors for re-operation. The MPV was
higher and statistically significant in patients with valvular
thrombus during re-operation (
p
<
0.001). MPV was deter-
mined to be an independent risk factor with 85% sensitivity
and 87% specificity.
Conclusion:
MPV and INR levels should be closely moni-
tored when designing individualised postoperative medical
treatment for patients undergoing heart valve re-operation.
Keywords:
platelet dysfunction, re-operation, heart valve pros-
thesis implantation, risk factors, mortality, retrospective studies
Submitted 13/3/13, accepted 7/6/13
Cardiovasc J Afr
2013;
24
: 251–254
DOI: 10.5830/CVJA-2013-044
Currently, cardiac valve diseases that require surgery are mainly
due to stenosis, insufficiency, and fixed valves in stenosis
accompanied by insufficiency. Acute rheumatic fever is the
main cause of mitral insufficiency in developing populations.
1
Improved survival rate after the primary surgery has led to
increased numbers of re-operations.
2
Therefore, in recent years
there has been a tendency towards increasing age of patients
undergoing re-operations on heart valve prostheses.
3
The major causes of re-operation include progression of
postoperative native valve disease after non-valve surgery,
and structural degeneration of bioprosthetic surgical valves.
Re-operations are more complicated than the initial procedure
due to adhesive processes around the heart, and the common
association of pulmonary hypertension (PHT). In addition,
replacement operations are often performed in functionally
compromised patients who tolerate complications less well.
4
In
the past, re-operative valve surgery was associated with a higher
mortality rate than with primary valve operations; however,
mortality and morbidity rates have decreased recently.
2,4,5
Although mechanical valves are long-lasting in young
patients, there is an increased risk for thrombogenic,
particularly thromboembolic, events and this requires long-
term anticoagulation therapy. Such thromboembolic events are
dependent on valve design, materials used and characteristics
of the patient.
6
Endocarditis, dehiscence, perivalvular leak and
pannus formation are commonly encountered with mechanical
and biological valves, while acute prosthetic valve thrombosis is
the main complication of mechanical valves.
In this study, we aimed to determine possible factors leading
to re-operation in patients undergoing mechanical valve
replacement and also to investigate the relationship between
valvular thrombus formation and mean platelet volume (MPV).
Methods
Between 2000 and 2005, 2 141 patients underwent heart valve
surgery in the Department of Cardiovascular Surgery of Dr
Siyami Ersek Thoracic and Cardiovascular Surgery Training and
Research Hospital, Istanbul, Turkey. Of the patients, 1 615 had
valve surgery, 370 had valve surgery with coronary artery bypass
graft (CABG) surgery, and 156 had mitral valve repair. During
the same time interval, the number of re-operations was 176.
Retrospective analysis was performed on the medical data
of 60 re-operated patients, but 17 were excluded from the study
due to missing data. Therefore, the study group was made up of
43 patients who had undergone mechanical valve implantation.
Patients who underwent bioprosthetic valve replacement during
the primary surgery were also excluded from the study to
achieve more homogenous results and to investigate whether
each parameter, namely valvular thrombus formation, pannus
formation and perivalvular leak, was an independent risk factor
for valve dysfunction and re-operation.
Data recorded included age, gender, valve type, valve size,
valve location, implantation position, warfarin use, INR level,
additional cardiac intervention, presence of left atrial thrombus,
valvular thrombus, pannus formation, perivalvular leak, left atrial
aneurysm, platelet count and MPV, bleeding after the primary
Department of Cardiovascular Surgery, Dr Siyami Ersek
Thoracic and Cardiovascular Surgery Training and
Research Hospital, Istanbul, Turkey
EBUZER AYDIN, MD,
FIKRI YAPICI, MD
