In this retrospective study, we investigated the risk factors for massive hemoptysis in patients with bronchiectasis and found that the presence of diabetes, lesions in two lobes, and involvement of the left lower lobe were associated with severe hemoptysis. However, this study also revealed that shorter disease courses (between 1 and 5 years) and patients with lesions involving the left lower lobe had a lesser chance of developing massive hemoptysis.
The most common causes of massive hemoptysis include bronchiectasis, tuberculosis, lung cancer, necrotizing pneumonia, and cryptogenic hemoptysis [8, 10]. There have been no reports on the incidence of massive hemoptysis in patients with bronchiectasis. In the present study, massive hemoptysis occurred in 16.09% of patients with bronchiectasis. In a previous survey, the prevalence of bronchiectasis was higher in elderly patients and women in Taiwan ; however, there was no significant difference in the incidence of severe hemoptysis between males and females, as well as among the different age groups in the present study.
Emerging evidence suggests that diabetic patients frequently report respiratory symptoms [12, 13] and are at an increased risk for several respiratory diseases [14–16]. However, bronchiectasis was not observed. We observed that diabetes was a risk factor for severe hemoptysis in patients with bronchiectasis. Animal studies suggest that diabetes may have a direct effect on the pulmonary vasculature. Pulmonary arteries from diabetic rats have been reported to be less responsive to vasodilatation because of increased endothelial dysfunction . Pulmonary vasculature may be affected by diabetic microvascular and macrovascular injuries . Hyperglycemia can lead to complicated infections in the lungs, such as tuberculosis, fungal, and non-tuberculous mycobacterial infections, which can cause massive hemoptysis.
The number of lobes involved by the lesions was found to be an independent predictor of massive hemoptysis in patients with bronchiectasis. We observed that the involvement of two lobes was a significant risk factor. Patients with lesions in the right upper lobe were more likely to develop massive hemoptysis. An interesting finding of our study was that lesions located in the left lower lobe rarely caused hemoptysis. In a long-term follow-up study of bronchial artery embolization for massive hemoptysis, the right bronchial artery was found to be the artery most responsible for bleeding . Another previous study found that the right bronchial artery was responsible for hemoptysis in patients with bronchiectasis . The right lobe is supplied by the right bronchial artery. This might be the reason for higher risk with right lobe involvement. However, why the right upper lobe was not a risk factor is still unknown. Therefore, further studies should be conducted on this topic. At present, the reasons for the lower incidence of massive hemoptysis in the left lower lobe are unclear. No studies have been conducted on this topic. There are also few reliable reports that could explain why the number of two or three lesion lobes was a risk factor for massive hemoptysis. Future prospective studies will be designed to assess the relationship between the number of lesion lobes and massive hemoptysis.
Nonbronchial systemic arteries such as the subclavian, internal mammary, and intercostal arteries, can be a significant source of massive hemoptysis . It may take a longer time for abnormal vessels to develop in patients with bronchiectasis; therefore, patients with disease courses between one and five years may develop severe hemoptysis. However, this needs to be confirmed by clinical evidence.
The limitations of this study are as follows: first, this was a retrospective study performed at only one hospital with a small number of patients with bronchiectasis, who were from the same region. Additional studies should be conducted in other regions to evaluate the risk factors for massive hemoptysis. Second, hemoptysis could not be quantified because the degree and extent of hemoptysis were rarely described in the medical records. In addition, not all laboratory findings and complications were included as potential risk factors; therefore, some risk factors might have been missed in this study. More studies on the risk factors for massive hemoptysis in patients with bronchiectasis are warranted.