Latest News on Pulmonary Artery : Nov 2020

CT-determined pulmonary artery diameters in predicting pulmonary hypertension.

This study was to determine if the diameters of pulmonary arteries measured from computed tomographic (CT) scans could be used 1) as indicators of pulmonary artery hypertension and 2) as a reliable base for calculating mean pulmonary artery pressure. The diameters of the main, left, proximal right, distal right, interlobar, and left descending pulmonary arteries were measured from CT scans in 32 patients with cardiopulmonary disease and in 26 age- and sex-matched control subjects. Diameters were measured using a special computer program that could display a CT density profile of the artery and its adjacent tissues. The upper limit of normal diameter for the main pulmonary artery was found to be 28.6 mm (mean + 2 SD). In the patient group, the diameters were correlated with data from cardiac catheterization. In these patients, a diameter of the main pulmonary artery above 28.6 mm readily predicted the presence of pulmonary hypertension. The calculated cross-sectional areas of the main and interlobar pulmonary arteries (normalized for body surface area [BAS]) were found to give the best estimates of mean pulmonary artery pressure (r = 0.89, P less than 0.001 and r = 0.66, P less than 0.001). Multiple regression analysis gave the useful equation: mean pulmonary artery pressure = -10.92 + 0.07646 X area of main pulmonary artery/BSA + 0.08084 X area of thright interlobar pulmonary artery/BSA (r = 0.93, P less than 0.0001). Because CT allows precise, noninvasive measurement of the diameter of pulmonary arteries, it can be of value in detecting pulmonary hypertension and estimating mean pulmonary artery pressure. [1]

Prognostic value of pulmonary artery pressure in chronic obstructive pulmonary disease.

In 175 patients with chronic obstructive lung disease (157 chronic bronchitic and 18 emphysematous patients) exhibiting moderate to severe airway obstruction (mean FEV1/vital capacity = 40.2 +/- 11.1%), cumulative survival rates calculated by the actuarial method were compared in subgroups according to the initial level of mean pulmonary artery pressure, pulmonary volumes, and arterial blood gases. Patients were catheterised between 1968 and 1972 and were followed for at least five years. The results emphasise the high prognostic value of PAP since survival rates after four and seven years were significantly lower in the subgroup with PAP greater than 20 mmHg (2.7 kPa). Certain other parameters (“driving” pressure across the pulmonary circulation, FEV1 and Paco2) appear to be equally good at predicting survival as PAP in these obstructed patients. The effect of age should be taken into account in prognostic studies such as ours since survival rates were significantly lower in patients over 60 years of age. In 64 patients who underwent a second right heart catheterisation at least three years after the first (average delay: 5.5 +/- 2 years), the prognostic value of changes in PAP, arterial blood gases, and pulmonary volumes was studied but with the exception of Pao2 was unremarkable. Further studies are needed in this field. [2]

A CT sign of chronic pulmonary arterial hypertension: the ratio of main pulmonary artery to aortic diameter.

The aim of this study was to determine whether the ratio of the diameters of the main pulmonary artery and of the ascending aorta (rPA), as assessed on computed tomography (CT), is predictive of pulmonary arterial hypertension (PAH). We undertook a retrospective review of 50 patients with a wide range of pulmonary and cardiovascular diseases, who had undergone both chest CT and pulmonary arterial pressure measurements at right heart catheterization. Two independent observers made measurements of the diameter of the main pulmonary artery and of the ascending aorta on a single defined CT section. Body surface area (BSA, n = 48), pulmonary arteriolar resistance (n = 39), total lung capacity (n = 40), and aortic pressures (n = 50) were also recorded. rPA and pulmonary arterial diameter (dPA) were positively related to mean pulmonary artery pressure (Rs = 0.74, p < 0.0005 for both analyses). For patients younger than 50 years of age, mean pulmonary artery pressure correlated more strongly with rPA than dPA (Rs = 0.77, p < 0.00005, compared with Rs = 0.59, p < 0.005); and vice versa for patients older than 50 years of age (Rs = 0.63, p < 0.005, compared with Rs = 0.75, p < 0.00005). Using a mean pulmonary artery pressure greater than 20 mm Hg as indicative of PAH and a value of rPA > 1, the sensitivity, specificity, and positive and negative predictive values for determining PAH were 70% (26/37), 92% (12/13), 96% (26/27), and 52% (12/23), respectively. On multivariate analysis, rPA was positively related to mean pulmonary artery pressure (p < 0.0005), and negatively related to age (p < 0.0005), but was not related to BSA. By contrast, dPA showed some dependency on BSA (p < 0.0005), as well as on mean pulmonary arterial pressure. In patients younger than 50 years of age, we have found a strong correlation between rPA and mean pulmonary artery pressure in a heterogeneous study population, and this relationship is independent of BSA and sex. The presence of the sign “rPA > 1” is simple in practical CT reading to determine; if this is identified, there is a very high probability of pulmonary arterial hypertension, and clinicians should be alerted to this possibility. [3]

Anomalous Orıgın of the Left Pulmonary Artery from the Ascendıng Aorta wıth Pulmonary Atresıa ın a 13 Year-old Girl

Aim: We reported a rare case of an anomalous origin of the left pulmonary artery (AOLPA) from the ascending aorta associated with pulmonary atresia and right sided aortic arch diagnosed at a relatively late age.

Case: 13 year-old girl presented to our pulmonology clinic with complaints of cough and dyspnea. On chest X-ray cardio thoracic ratio was increased and shadow of the arch was not seen on the left. On her echocardiography pulmonary arteries couldn’t be demonstrated. Computed tomography angiography was performed to the patient. Right sided arch aorta with pulmonary atresia associated with an anomalous origin of the left pulmonary artery from the ascending aorta with a well developed collateral blood supply to the right lung and coexisting pulmonary infection was detected. She was managed medically. She is on the first year of her follow up. Her medical status is stable.

Conclusion: We presented a case of relatively rarely seen anomalous origin of the left pulmonary artery from the ascending aorta with a rarely seen association of pulmonary atresia and wanted to take attention to its presentation in a late childhood. [4]

Pulmonary Arterial Hypertension and Cancer: An Update on Their Similarities

Pulmonary arterial hypertension (PAH) is characterized by an increase resistance of the vascular wall from pulmonary arteries leading to vascular lumen occlusion, right ventricular failure, and death. PAH has been described for many years, as a cardiovascular disease affecting the lungs. Whatever the initial cause, pulmonary arterial hypertension involves the vasoconstriction of blood vessels connected to and within the lungs. In addition, the increased workload of the heart causes hypertrophy of the right ventricle, making the heart less able to pump blood through the lungs, causing right heart failure. Recently several groups have demonstrated that PAH is a disease of excess proliferation and impaired apoptosis similar to neoplasia. Although the fundamental cause remains elusive, many predisposing and disease-modifying abnormalities occur, including endothelial injury/dysfunction, bone morphogenetic protein receptor-2 gene mutations, decreased expression of the K+ channel (Kv1.5), transcription factor activation [hypoxia-inducible factor-1 (HIF-1 )], expression of survivin, and increased expression/activity of both serotonin transporters and platelet-derived growth factor receptors. Together, these abnormalities create a cancer-like, proliferative, apoptosis-resistant phenotype. From these observations, it has been established some similarities between PAH and cancer.

Therefore, in this review, we will discuss the essential alterations in pulmonary arterial hypertension as compared to cancer cell which has been alluded to as the “cancer paradigm”. Based on these similarities, we can imagine that future therapies used to treat cancer could also work for PAH. [5]

Reference

[1] Kuriyama, K.E.I.K.O., Gamsu, G.O.R.D.O.N., Stern, R.G., Cann, C.E., Herfkens, R.J. and Brundage, B.H., 1984. CT-determined pulmonary artery diameters in predicting pulmonary hypertension. Investigative radiology, 19(1), pp.16-22.

[2] Weitzenblum, E., Hirth, C., Ducolone, A., Mirhom, R., Rasaholinjanahary, J. and Ehrhart, M., 1981. Prognostic value of pulmonary artery pressure in chronic obstructive pulmonary disease. Thorax36(10), pp.752-758.

[3] Ng, C.S., Wells, A.U. and Padley, S.P., 1999. A CT sign of chronic pulmonary arterial hypertension: the ratio of main pulmonary artery to aortic diameter. Journal of thoracic imaging14(4), pp.270-278.

[4] Selcuk, T., Bilgili, C., Otcu, H., Savas, Y., Cakmak, G. and Cengel, F., 2015. Anomalous Orıgın of the Left Pulmonary Artery from the Ascendıng Aorta wıth Pulmonary Atresıa ın a 13 Year-old Girl. Journal of Advances in Medicine and Medical Research, pp.719-723.

[5] Delom, F. and Fessart, D., 2014. Pulmonary arterial hypertension and cancer: An update on their similarities. Annual Research & Review in Biology, pp.20-37.

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