Pulmonary hypertension: intothe 21st centuryKeith McNeil

Ten years ago, most physicians consideredpulmonary hypertension (PH) as adisease known as ‘primary pulmonaryhypertension’ (PPH). The assessment andtreatment of these patients was largelyconfined to specialist units based in andaround lung transplant programmes.Indeed, apart from lung transplantation,effective treatment was limited to con-tinuous intravenous prostacyclin deliveredvia a Hickman line, in itself usually usedas a bridge to transplantation. Not sur-prisingly, therapeutic nihilism was rife,patients were left undiagnosed until thelate stages of the disease, and the outlookfor most was universally grim.

The association of PH with other condi-tions has of course long been recognised.Significant PH complicating advanced leftheart disease was, and still is, a relativecontraindication to heart transplantation,and PH in association with severe mitralstenosis often figured in Fellow of the RoyalAustralasian College of Physicians examin-ation cases. The nocturnal oxygen trials inpatients with advanced chronic obstructivepulmonary disease were effectively addres-sing the PH and consequent right heartfailure related to chronic hypoxaemia.However apart for these historical associa-tions, PH associated with other disorderssuch as liver disease, connective tissue dis-eases, haematological disorders, HIV infec-tion, thyrotoxicosis and hereditaryhaemorrhagic telangiectasia to name a few,was under recognised.

Much however has changed in the past10 years. The availability of several effectiveoral treatment options for pulmonary arter-ial hypertension (PAH) coupled with thediscovery of the gene responsible for PPH

(now referred to as idiopathic PAH) hasseen an explosion of interest in all forms ofthis disorder. Several expert consensus con-ferences have redefined the classification ofPH, reflecting our growing understandingof the pathologies involved and how theseinfluence diagnostic and therapeutic deci-sion making. An evidence based treatmentalgorithm for PAH has been endorsed bythe PH community at large and a numberof international cardiac and respiratory soci-eties. Here in Australia, the recently formedPulmonary Hypertension Society ofAustralia and New Zealand has arisen toface the challenge of a large and increasingpatient cohort, which cannot now bemanaged by the small number of clinicalexperts in the transplantation centres ineach state. Patients across the age rangenow rely very much on general practi-tioners (GPs) and specialists from a widevariety of backgrounds to be increasinglyfamiliar with this disorder.Strange et al1 provide us with a unique

insight into the epidemiology of PH inAustralia. In a world first, they havelooked at the prevalence of PH in a com-munity setting, in a discrete (representa-tive) population, hailing from a region inWestern Australia. The diagnosis of PHwas based on tricuspid regurgitant (TR)jet velocities reported on echocardio-grams, enabling the calculation of rightventricular systolic pressure, which if ele-vated (>40 mm Hg being the acceptedcut-off value) in the absence of right ven-tricular outflow obstruction, has beenshown to be a reliable estimate of systolicpulmonary artery pressure (sPAP).The study performed was retrospective,

and was performed in a cohort ofpatients referred for echocardiography,implying they all had symptoms and/orsigns suggestive of cardio-respiratorydisease. Although this is a biased sample,combined with the fact that not all

patients had TR identified, the studywould, if anything, have led to a conser-vative estimate of the number of patientswith PH in the whole community.

So what did this study tell us? First, itshowed in this cohort, that PH is associatedwith excess mortality both in its own right(as idiopathic PAH) and when associatedwith other diseases. Furthermore, the studyshowed, compared with historical cohorts,and in line with current trial based evi-dence, that PAH specific treatment is effect-ive. If for no other reasons, these twofindings alone provide a compelling case forearly diagnosis and appropriate therapeuticintervention in these patients.

The study also provided reinforcementof findings from a number of overseas epi-demiological studies referred to in thepaper. In our western society, PH compli-cating left heart disease is the mostcommon association, and accounted for68% in the Armadale study. This findingalso highlights the necessity to perform aright heart catheter investigation in theassessment of PH patients to confirm/exclude raised left atrial pressure as acause, with all the treatment implicationsthis would imply.

The Armadale study also showed us thatchronic thromboembolic PH (CTEPH) is ascommon as all forms of PAH combined.The import of this is that a different assess-ment and vastly different treatment algo-rithm needs to be applied to this group ofpatients. CTEPH is the only form of severePH with a ‘cure’. A surgical procedureknown as pulmonary endarterectomy(which removes the obstructive material inthe pulmonary arterial tree) is now offeredin a number of centres in Australia.Outcomes are better when patients arereferred early in the course of the disease,before the onset of severe right heart failure.

The paper also highlights the currentbane of all PH physicians—the unaccept-able delay in referral of these patients fordefinitive intervention. It is not uncom-mon, in fact it is the rule, that there isusually a gap of more than 2 years fromthese patients first presenting with symp-toms to a diagnosis being made. The onsetof symptoms in these patients, usuallydebuting with exercise or activity, repre-sents advanced pulmonary vascular diseaseassociated with the onset of right

Correspondence to Professor Keith McNeil The PrinceCharles Hospital Rode Road, Chermside. Brisbane,Australia 4032Keith_McNeil@health.qld.gov.au

1760 Heart December 2012 Vol 98 No 24

Editorial

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ventricular compromise. The so called‘EARLY’ study2 in patients with class IIsymptoms, showed in this cohort, pulmon-ary vascular resistance values 5–10 timesnormal, with a striking rate of decline overjust 6 months in untreated patients.

The Armadale study thus synthesises anumber of aspects of the epidemiology andnatural history of PH in the real world, andreinforces the need for all medical practi-tioners, be they GPs or specialists from anybackground, to remain vigilant and open to

the possibility of PH as a diagnosis or com-plication in patients presenting with unex-plained breathlessness and/or fatigue.Unexplained breathlessness is simply that,it is not a diagnosis and in the modern erawith the diagnostic tools we have at ourdisposal, it is simply not acceptable.

Competing interests None.

Heart 2012;98:1760–1761.doi:10.1136/heartjnl-2012-302609

REFERENCES1. Strange G, Playford D, Stewart S, et al.

Pulmonary hypertension: prevalence and mortalityin the Armadale echocardiography cohort. HeartPublished Online 3 July 2012; 10.1136/heartjnl-2012-301992.

2. Galie N, Rubin L, Hoeper M, et al. Treatment ofpatients with mildly symptomatic pulmonary arterialhypertension with bosentan (EARLY study): adouble-blind, randomised controlled trial. Lancet2008;37:2093–100.

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doi: 10.1136/heartjnl-2012-302609 2012 98: 1760-1761Heart

 Keith McNeil centuryPulmonary hypertension: into the 21st

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