Blood vessel problems in the fingers and toes cause ‘Raynaud’s phenomenon’. Problems in the kidneys can cause dramatic renal failure. Problems in the lungs cause a condition called ‘pulmonary hypertension’.
In the last 15 years there has been a progressive increase in the number of medical treatments available for treatment of pulmonary hypertension. With this has come an increased amount of research into what had previously been something of an ‘orphan’ condition. Treatment (with prostacyclin analogues; with endothelin receptor antagonists (Bosentan); with the phosphodiesteraseE5 inhibitor Sildenafil, sometimes known as Viagra™) remains expensive and tightly controlled. Often treatment is not accessed until people have severe, or end stage, pulmonary hypertension. I have a handful of patients with scleroderma, and looked after many such patients when working in London. In London the bar for access to treatment for pulmonary hypertension seemed significantly lower than it is in Australia.
So I read, with much interest, a recent report from Austria/Germany/California about the impact of even high-normal pulmonary artery pressures (PAP) on the exercise tolerance of people with scleroderma. Twenty-nine patients with systemic sclerosis but no evidence of lung or heart disease participated in this trial. They all had normal resting pulmonary artery pressures on echocardiogram, but demonstrated an increase in systolic pulmonary artery pressure with exercise ( to over 40mmHg) or a deceased exercise capacity (peak VO2 <75% predicted). They all proceeded to have a more accurate measure of pulmonary artery pressure obtained via catheterization of the right side of the heart ( an invasive procedure, something like an angiogram). A cardiopulmonary exercise test was performed while the right heart catheter was in place to measure changes in PAP with exercise. Subsequently – right heart catheter now removed, but within 48 hours - they went on to perform a 6 minute walk test (6MWT). This test is as simple as it sounds. The supervisors of the 6MWT were not aware of the right-heart-catheter results.
The median resting PAP of the group was 17mmHg. A resting PAP greater than that level was associated with a reduced distance walked on 6MWT, reduced peak V02 and reduced maximal work rate. An early increase in PAP at low work levels showed essentially the same correlations, but PAP at peak exercise did not show an association with distance walked on 6MWT or peak V02 and maximal work rate.
These results are very interesting, and could be quite important. They suggest that people with scleroderma who have high-normal pulmonary artery pressures, and particularly those who show an early rise in PAP during exercise, have a lowered exercise capacity. The possibility that these people may have a worse prognosis needs to be considered and investigated. (There is evidence that patients with scleroderma, pulmonary fibrosis (which is often associated with scleroderma) and a resting PAP > 17mmHg have decreased survival when compared with patients whose PAP was <17mmhg (5- year survival 16.7% vs 62.2%)). Ultimately it may well turn out to be important to treat such patients with even high-normal PAP early with the available medications.
The wheels of evidence-based medicine turn slowly for ‘orphan’ conditions such as pulmonary hypertension. Translation of this sort of research, fascinating though I may find it, into meaningful therapeutic changes will take many years.
I have had no end of trouble with hyperlinks and pics on this post - will post table from the paper seperately.
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