PERCUTANEOUS TRANSVENOUS MITRAL COMMISSUROTOMY IN JUVENILE MITRAL STENOSIS

Abstract

INTRODUCTION
Juvenile mitral stenosis is predominantly seen in
developing countries where rheumatic fever is still very
common(1,2). Mitral stenosis (MS) represents a different
pattern of rheumatic fever characterized by a
"smouldering" sub-clinical course with majority of the
lesions being diagnosed in older patients (fifth to sixth
decade) than mitral regurgitation or aortic regurgitation
of rheumatic origin (3-4). However, in developing
countries, MS progresses more rapidly, presumably due
to either a more severe rheumatic injury or repeated
episodes of carditis due to streptococcal infections,
resulting in severe symptomatic MS in the early to mid
teenage and the early twenties(5). MS in the under 21
years olds therefore attests to severe rheumatic fever
and also carries poorer prognosis. Patients exhibit
severe pulmonary oedema, early severe pulmonary
hypertension and eventually severe right ventricular
failure. The most effective method of alleviating this
poor prognostic end-stage disease is aggressive control
of rheumatic fever in the community, in hospitals and
clinics. However, there are many patients who present
with already severe symptomatic MS at less than
twenty-one years of age and require intervention.
Closed heart surgery with surgical commissurotomy has
been the most common form of intervention in Kenya
but this has now been replaced by Percutancous
Transvenous Mitral Commissurotomy (PTMC).
Appropriate balloon sizes for very small patients due
to age or cardiac cachexia has however been a significant
problem with the previous balloon systems especially
the Inoue cathetar system. With the introduction of the
Multi- track balloon systems it has been possible to
perform this intervention effectively with more case and
safety even in the smallest/youngest of patients such
as those seen in developing countries like Kenya(6).
The authors describe a series of uniquely young patients
with MS and their interventions with PTMC using the
Multitrack system.
PATIENTS AND METHODS
Out of over 200 patients done PTMC so far, forty
five(45) patients aged less than 21 years underwent PTMC
in 3 hospitals in Nairobi between 1996 and 2001 (namely
The Mater Hospital, Kenyatta National Hospital and Nairobi
Hospital). Majority were referred from other hospitals and
health institutions outside Nairobi. They were all symptomatic
patients (NYHA functional class 11 to IV) with severe mitral
stenosis due to rheumatic heart disease. They all underwent
transdioracie and trans-oesophageal echocardiograms,
electrocardiography, chest X-ray and pre-cathetarisation
laboratory tests. Wilkins score tests were used to determine
leaflet suitability for valvotomy(7). Mitral valve areas were
determined by both pressure half-time and plannimetry and
average values used. Patients with more than 2+ mitral
regurgitation were excluded. The mitral annulus diameter was
used to select dilating balloon sizes (sum of balloon diameter
- 90-100% annulus diameter)(8).
Left and right heart cathetarisation was done under local
anaesthesia. A sheath was inserted into the left femoral artery
and pigtail catheter introduced to identify the aortic root and
also monitor pressures. Transeptal puncture was then performed
from the fight femoral vein utilizing Mullin's dilator sheath
system and Brockenbrough needle in the standard method.
Heparin IV 100iu/kg (or 5,000 iu for > 50kg) was then given.
After simultaneous LA-LV pressure recordings, (figurel)
mitral valve dilatation was done using the Multi-track double
balloon technique (figure 2) (8,9) . The LA-LV pressures
were repeated and the procedure concluded. After 24hrs
observation in hospital, the patients were discharged home
for follow-up. Post PTMC echocardiograms were performed
before discharge and follow-up appointments scheduled at six
monthly then annually or otherwise according to area of
residence.
RESULTS
The patients were aged 9-20 years (mean 14±2.6),
comprising of 16 boys and 29 girls. They were all
symptomatic and presented in NYHA functional class
11 to IV, They weighed between 18 - 57 Kg (mean
35±10.3kg). Nine patients had active rheumatic fever
at time of presentation and needed bed rest, antiinflarnmatories
and antibiotics treatments prior to PTW.
All the selected cases for PTMC did not have significant
lesions on the other valves except for three cases where
combined mitral and aortic stenosis was present and
balloon dilatation for both valves was done at the same
time. Fight of the patients had atrial fibrillation and of
these three had thrombi in the left atrial appendage.
No patients in sinus rhythm exhibited left atrial thrombi
on trans-esophaged echocardiography. On
echocardiography all the patients had mitral valve areas
of less than 1.0cm2. Twenty-five patients (56%) had
44 EAST AFRICAN MEDICAL JOURNAL March 2003
estimated pulmonary artery pressure (by tricuspid
regurgitation jet velocity) greater than 75 mmHg and
evidence of LV systolic dysfunction was present in
fourteen (29%). The Wilkin's echo score for PTMC
ranged between 7 and 11 with mean score of 8.6.
Results of the PTMC using Multi- track double balloon
technique are shown in Table 1. There were no
significant intra-procedum complications in any of
these patients and no mortality. One boy however had
to be returned to the cath lab for repeat ballooning due
to technical difficully in positioning balloons in an
extremely small left ventricle and massive left atrium
with greatly bulging atrium septum. One boy who had
HIV/AIDS syndrome died later in hospital due to
opportunistic infections.