The exercise response in pulmonary hypertension (PH) has characteristic features, including decreased peak oxygen consumption, increased ventilatory inefficiency (VE/VCO2 slope) and widened alveolar-arterial gradient. These features can be used in diagnosing PH or distinguishing it from other causes of breathlessness. Many of the measurements from CPX are effort-independent, unlike the 6-min walk test, and can be used to discriminate uncontrolled PH from other factors which may affect peak capacity, such as obesity. We wished to evaluate the clinical and economic impact of CPX in PH.Methods
We performed a retrospective analysis of 552 studies performed between August 2007 and August 2010. The impact of these tests was assessed by reviewing clinic letters and multidisciplinary team minutes.Results
As a direct consequence of CPX, (1) 69 (13%) new non-PH diagnoses were made leading to changes in management and non-PH therapy in 18 (3%); (2) cardiac catheterisation was avoided in 69 (13%) and identified as necessary in 5 (1%), with a net saving of £179.5k; (3) 33 non-PH causes for patients' symptoms were identified, preventing the addition of unnecessary and expensive therapies, saving £318.9k; 4) four patients were identified as needing additional therapy, albeit at greater cost (£26.6k); 5) finally, CPX facilitated confident discharge of patients in 38 (7%). The total saving using CPX over 3 years was £457.9k. Appropriate charging structures are not in place for CPX and testing was carried out using research facilities, however, a new national tariff for CPX is set at £235/test. This would still result in net saving of £328.2k (a gain of £594/test) in addition to the clinical benefit. We identified further savings of £93.6k which could have resulted from use of CPX earlier in the diagnostic process, increasing the net gain from £594 to £764 per test.Conclusion
CPX provides clinical and financial benefit by directing investigations and treatments in a substantial number of cases. CPX prevented patients undergoing expensive and invasive investigations to establish diagnoses and monitor progression. CPX also improved appropriate use of therapies by characterising patients' functional capacity and identifying when alternative conditions were responsible for patients' deterioration.