Department of Cardiology, Royal Free Hospital, Pond Street, London NW3 2QG, UK
Correspondence to: E-mail: gerry.coghlan{at}royalfree.nhs.uk
We welcome the comments of Busteed et al., which largely support our findings. Their work is an excellent example of how a screening programme can improve the management of patients with systemic sclerosis.
The issue of unobtainable triscuspid gradients was not dealt with extensively in our paper. However, we generally use either contrast echocardiography to augment the signal or use pulmonary acceleration times to identify patients with possible pulmonary arterial hypertension (PAH). We did not have enough data on this group of patients to comment on the value added by these techniques.
In terms of gas transfer in the presence of lung fibrosis, we have taken the view that if the reduction of gas transfer is concordant with the reduction in total lung volumes, this should not lead to catheterization; such an approach significantly reduces the number of patients one might consider referring.
Finally, in respect of the outcome in mild PAH, there are as yet no published data on this subject. However, we have some preliminary data which it may be useful to share. We have followed 63 patients with mild systemic sclerosis associated PAH (grade 1 or 2 dyspnoea or mean pulmonary pressure of less than 30 mmHg) for up to 4 yr (number at risk at 4 yr = 27). Twenty of these patients have developed advanced PAH, requiring disease-specific therapy over the 4 yr of follow-up, and the annual mortality stands at 10%, with six of 15 dying from right ventricular failure due to pulmonary hypertension. Thus, while awaiting formal confirmation, we suggest that it is wise to assume that early PAH is not a benign phenomenon.
We have also read with interest the contribution of Dr Gupta. As noted above, we correlate gas transfer with total lung capacity, but forced vital capacity (FVC) is equally appropriate. In our paper we strove to avoid problems due to interstitial lung disease (ILD) by excluding those with significant lung disease from the cohort in which we examined the relation between gas transfer and catheterization findings. We believe, therefore, that the lack of correlation shown in our paper will be reproduced when correction for the impact of ILD is attempted. However, we await with interest Dr Gupta's findings; we caution that echocardiography should not be used as the definitive diagnostic test for PAH. Though echocardiography performed moderately well, it failed to identify postcapillary pulmonary hypertension and failed to identify a significant number of patients with advanced PAH. There may well be clinical scenarios where one chooses not to proceed to invasive evaluation, but for the purposes of publication there can be no justification for not obtaining a firm diagnosis.
The author has declared no conflicts of interest.
Accepted 23 July 2004
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