Occlusive venopathy phenotype in hereditary pulmonary arterial hypertension

Franchi, Sonia Meiken; Aiello, Vera D.; Lopes, Antonio Augusto

doi:10.1590/S0066-782X2011000900019

Abstracts

A 33-year-old male with severe hereditary pulmonary arterial hypertension had a confirmed diagnosis of occlusive venopathy and microvasculopathy. He remained stable for three and a half years on oral sildenafil, 75 mg t.i.d. (six-minute walked distance of 375 m vs 105 m at baseline), but required addition of bosentan (125 mg b.i.d.), subsequently. Despite the fatal outcome at five years post-diagnosis, the observations suggest a potential usefulness of vasodilators as a bridge for lung transplant in selected cases with significant venous/capillary involvement. The occurrence of veno-occlusive and capillary lesions in the familial form of pulmonary arterial hypertension reinforces the difficulties with the current classification of the disease.

Pulmonary hypertension; pulmonary occlusive venopathy; microvasculopathy; hereditary pulmonary arterial hypertension; sildenafil

Um homem de 33 anos com hipertensão arterial pulmonar hereditária teve um diagnóstico confirmado de venopatia oclusiva e microvasculopatia. O paciente permaneceu estável por 3 anos e meio recebendo sildenafila via oral, 75 mg 3x/dia (teste de caminhada de seis minutos de 375 m vs 105 m basal), mas necessitou da adição de bosentana (125 mg 2x/dia) posteriormente. A despeito do desfecho fatal após 5 anos, as observações sugerem um utilidade potencial dos vasodilatadores como uma ponte para o transplante de pulmão em casos selecionados com envolvimento venocapilar significante. A ocorrência de lesões veno-oclusivas e capilares na forma familiar da hipertensão arterial pulmonar enfatiza as dificuldades com a atual classificação da doença.

Hipertensão pulmonar; venopatia oclusiva pulmonar; microvasculopatia; hipertensão arterial pulmonar hereditária; sildenafila

Un hombre de 33 años con hipertensión arterial pulmonar hereditaria tuvo un diagnóstico confirmado de venopatía oclusiva y microvasculopatía. El paciente permaneció estable 3,5 años recibiendo sildenafila vía oral, 75mg 3x/ día (test de caminata de seis minutos de 375m vs. 105m basal), pero necesitó adición de bosentánana (125mg 2x/día) posteriormente. A despecho del desenlace fatal después de 5 años, las observaciones sugieren una utilidad potencial de los vasodilatadores como un puente para el transplante de pulmón en casos seleccionados con compromiso venocapilar significativo. La ocurrencia de lesiones veno-oclusivas y capilares en la forma familiar de la hipertensión arterial pulmonar enfatiza las dificultades con la actual clasificación de la enfermedad.

Hipertensión pulmonar; venopatía oclusiva pulmonar; microvasculopatía; hipertensión arterial pulmonar hereditaria; sildenafil

CASE REPORT

Instituto do Coração (InCor), Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP - Brazil

Mailing address

ABSTRACT

A 33-year-old male with severe hereditary pulmonary arterial hypertension had a confirmed diagnosis of occlusive venopathy and microvasculopathy. He remained stable for three and a half years on oral sildenafil, 75 mg t.i.d. (six-minute walked distance of 375 m vs 105 m at baseline), but required addition of bosentan (125 mg b.i.d.), subsequently. Despite the fatal outcome at five years post-diagnosis, the observations suggest a potential usefulness of vasodilators as a bridge for lung transplant in selected cases with significant venous/capillary involvement. The occurrence of veno-occlusive and capillary lesions in the familial form of pulmonary arterial hypertension reinforces the difficulties with the current classification of the disease.

Keywords: Pulmonary hypertension; pulmonary occlusive venopathy; microvasculopathy; hereditary pulmonary arterial hypertension; sildenafil.

Introduction

Hereditary transmission of pulmonary arterial hypertension (PAH) has been identified in 6% to 10% of PAH subjects. Bone morphogenetic protein type-2 receptor (BMPR2) gene mutations have been reported in 50% to 90% of families with PAH¹. Pulmonary occlusive venopathy (POV, formerly pulmonary veno-occlusive disease) is a rare form of histological presentation of PAH, found in approximately 5% of biopsies from patients with unexplained pulmonary vascular disease^2,3. Even less frequent is the familial presentation of POV. One single family report, with BMPR2 mutation detected⁴, led to the inclusion of POV (and pulmonary microvasculopathy, formerly pulmonary capillary hemangiomatosis) in the first diagnostic category of pulmonary hypertension (namely, PAH). One striking characteristic of POV is the poor outcome, in some cases, following vasodilator administration (particularly epoprostenol), with development of massive pulmonary edema and death^5,6. We report a case of confirmed POV associated with microvasculopathy, with familial history of PAH, that remained stable for five years on oral vasodilator therapy, without development of pulmonary edema.

Case report

A 33-year old male was admitted in October 2002, with recent and progressive dyspnea, edema and ~10 kg weight loss. Two sisters of his had died of "primary pulmonary hypertension" at the ages of 11 and 14 years. There were no further data suggesting specific cardiac, respiratory or infectious diseases, joint or skin abnormalities or use of appetite suppressants. On physical examination he had a "weak" (undernourished) appearance (weight 60 kg; height 1.82 m), mild liver enlargement and lower limb edema. A loud pulmonic valve closure sound was heard on the precordium. Lung examination revealed mild rhonchi and fine rales on both sides, which disappeared completely following diuretic administration. Complementary imaging and laboratory tests for heart liver and lung disease, chronic thromboembolism, schistosomiasis, human immunodeficiency virus infection and connective tissue disorders were negative. DNA sequencing methodologies revealed no mutations in the coding region of the patient's BMPR2 gene. Right heart catheterization data were compatible with pulmonary arterial hypertension. Both inhaled nitric oxide and oral sildenafil were effective in reducing pulmonary vascular resistance. A marked elevation of the wedge pressure was registered during nitric oxide inhalation (Table 1). Open-lung biopsy confirmed the suspicion of pulmonary occlusive venopathy and depicted the concomitance of microvasculopathy (Figure 1).

Thumbnail

During the first two years of oral sildenafil therapy (75 mg t.i.d.), there was a sustained improvement in the six-minute walked distance (105 m and 399 m, respectively at baseline and 2 years) associated with an increase in Doppler-echocardiographic estimate of pulmonary (and systemic) flow (pulmonary systolic flow velocity-time integral of 0.10 m and 0.19m, respectively). Pulmonary edema was never observed. The clinical status deteriorated from three and a half to 4 years (walked distance 375 m to 261 m); bosentan was added (125 mg b.i.d., orally, final dose), and the patient was listed for lung transplantation. He died at five years post-diagnosis, despite the use of the combined therapy. Autopsy findings confirmed the initial diagnosis.

Discussion

The present case adds elements to the discussion on the familial presentation of POV. First, since we do not have histological data from other family members (especially those who died of "primary pulmonary hypertension"), we cannot affirm that the phenotype of the other PAH subjects was really POV. The same point was mentioned by Runo et al⁴ and co-workers in their family report. Thus, it remains to be clarified whether POV is an individual expression of pulmonary vascular disease in these families or affects all family members. Furthermore, the frequent concomitance of occlusive venopathy and microvasculopathy foci in lung tissue has brought the possibility that they represent a morphological spectrum of the same entity. Second, since we did not analyze other genes of the TGF-beta superfamily, we cannot exclude mutations in these genes as a possible explanation for the familial character of the disease in the present report. Alternatively, the possibility remains that POV with familial PAH presentation is related to genes other than the TGF-beta family. Anyway, the concomitance of POV/microvasculopathy and familial presentation reinforces the limitations of the current classification of pulmonary hypertension, where these conditions appear separately in the first diagnostic category (pulmonary arterial hypertension)⁷.

Another point to be discussed is the relatively stable clinical course on vasodilator therapy. High-dose sildenafil was administered from the beginning, since treatment was started far before the publication of the SUPER-1 study⁸. Despite the evidence of the beneficial effects of sildenafil and bosentan in PAH, there have been no reports on the use of these drugs in rare conditions, as is the case of POV/microvasculopathy. One possible explanation for the non-occurrence of pulmonary edema in the present case is the presence of markedly obstructive lesions at the arterial side of pulmonary circulation (Figure 1). On the other hand, preliminary observations in the catheterization laboratory suggested that sildenafil, in particular, may have different effects on the pulmonary venous circulation as compared with other vasodilators, such as inhaled nitric oxide⁹. This is in agreement with our initial observations of mild elevation of pulmonary wedge pressure following sildenafil (single dose) administration and points toward the need for controlled studies to investigate the effects of this drug (as well as other vasodilators) in the setting of PAH with significant venous involvement.

Conclusions

Pulmonary occlusive venopathy and microvasculopathy may occur concomitantly in hereditary PAH. In selected cases, chronic oral therapy with sildenafil may be of help as bridge to lung transplantation. Controlled studies are obviously needed in this way. However, the rare character of the disorder is a clear limitation to the analysis of large series.

Potential Conflict of Interest

No potential conflict of interest relevant to this article was reported.

Sources of Funding

There were no external funding sources for this study.

Study Association

This study is not associated with any post-graduation program.

References

1. Machado RD, Pauciulo MW, Thomson JR, Lane KB, Morgan NV, Wheeler L, et al. BMPR2 haploinsufficiency as the inherited molecular mechanism for primary pulmonary hypertension. Am J Hum Genet. 2001;68(1):92-102.
2. Wagenvoort CA. Lung biopsy specimens in the evaluation of pulmonary vascular disease. Chest. 1980;77(5):614-25.
3. Bjornsson J, Edwards WD. Primary pulmonary hypertension: a histopathologic study of 80 cases. Mayo Clin Proc. 1985;60(1):16-25.
4. Runo JR, Vnencak-Jones CL, Prince M, Loyd JE, Wheeler L, Robbins IM, et al. Pulmonary veno-occlusive disease caused by an inherited mutation in bone morphogenetic protein receptor II. Am J Respir Crit Care Med. 2003;167(6):889-94.
5. Palmer SM, Robinson LJ, Wang A, Gossage JR, Bashore T, Tapson VF. Massive pulmonary edema and death after prostacyclin infusion in a patient with pulmonary veno-occlusive disease. Chest. 1998;113(1):237-40.
6. Okumura H, Nagaya N, Kyotani S, Sakamaki F, Nakanishi N, Fukuhara S, et al. Effects of continuous IV prostacyclin in a patient with pulmonary veno-occlusive disease. Chest. 2002;122(3):1096-8.
7. Simonneau G, Robbins IM, Beghetti M. Update clinical classification of pulmonary hypertension. Proceedings of the 4th World Symposium on Pulmonary Hypertension, February 2008, Dana Point, California, USA. J Am Coll Cardiol. 2009;54(1 Suppl):S43-54.
8. Galiè N, Ghofrani HA, Torbicki A, Barst RJ, Rubin LJ, Badesch D, et al. Sildenafil Use in Pulmonary Arterial Hypertension (SUPER) Study Group. Sildenafil citrate therapy for pulmonary arterial hypertension. N Engl J Med. 2005; 353: 2148-57. Erratum in: N Engl J Med. 2006;354(20):2400-1.
9. Michelakis E, Tymchak W, Lien D, Webster L, Hashimoto K, Archer S. Oral sildenafil is an effective and specific pulmonary vasodilator in patients with pulmonary arterial hypertension: comparison with inhaled nitric oxide. Circulation. 2002;105(20):2398-403.