Pulmonic regurgitation pathophysiology
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Pulmonic regurgitation Microchapters |
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Diagnosis |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Aravind Kuchkuntla, M.B.B.S[2], Aysha Anwar, M.B.B.S[3]
Overview
The pathophysiologic mechanism of pulmonic regurgitation includes right ventricular overload resulting in right ventricular remodeling and progressive decline in function. The rate of decline in right ventricular systolic function is affected by associated conditions such as peripheral pulmonary artery stenosis and pulmonary hypertension which further increase the severity of pulmonary regurgitation.
Pathophysiology
The pulmonic regurgitation usually occurs by one of the following mechanisms:[1]
Acquired alteration in the valvular leaflet morphology[2]
- The development of pulmonic regurgitation due to tophus valvular vegetations has been reported in a case. The patient reported had long-standing cyanotic congenital heart disease and developed hyperuricemia secondary to polycythemia. The possible mechanism of development of the vegetations involved hemodynamic valvular trauma in the setting of sustained hyperuricemia and subsequent dystrophic calcification at primary tophus lesion.
- On gross pathology vegetative lesions observed.
- Polarized light microscopy of the material taken from the pulmonic valve demonstrated negatively birefringent crystals.
Idiopathic dilatation of the pulmonary artery (IDPA)[3][4][5]
- The exact pathogenesis of dilatation of the pulmonary artery is not fully understood. The demonstration of the disease among pediatric population signals the congenital nature of the etiology. Main pulmonary artery and the origin of its right and left main pulmonary arteries are majorly affected. It is thought that pulmonary artery dilatation is mediated by the unequal division of truncus arteriosus communis. Other proposed mechanisms include maldevelopment of the whole pulmonary tree and the association of hypoplastic aorta with dilated.
Pulmonary artery aneurysm[3][4][6]
- It is thought that the development of pulmonary artery aneurysm is mediated by either the congenital weakness or cystic medial degeneration of the pulmonary artery walls. An association between cystic medial degeneration and increased hemodynamic forces then leads to aneurysm formation. Pulmonary artery aneurysms have been associated with structural cardiac and vascular abnormalities, vasculitis, and infection (such as syphilis.
Congenital absence or malformation of the valve
Increasing regurgitation causing right ventricular volume overload[7]
- Patients with pulmonic regurgitation develop chronic right ventricular overload resulting in right ventricular remodelling and progressive decline in function. The rate of decline in right ventricular systolic function is affected by associated conditions such as peripheral pulmonary artery stenosis and pulmonary hypertension which further increase the severity of pulmonary regurgitation. Among patients with increased pulmonary artery pressure from dysfunction of left ventricle or residual pulmonary artery stenosis increases the severity of pulmonary regurgitation. Progressive dilation of the right ventricle results in functional tricuspid regurgitation and increases the risk of developing arrhythmias.
- The diastolic pressure difference between right ventricle and pulmonary artery is usually very small and steers the pulmonic valve regurgitation. The right ventricular stiffness due to right ventricular hypertrophy (such as in Tetralogy of Fallot) and fibrosis, increases the ventricular diastolic pressure, decreasing the gradient thus causing regurge. A slight increase in the intrathoracic pressure (such as among ventilated patients) can accentuate the pulmonary regurgitation considerably.[8]
- The severity of regurgitant jet is dependent on:[7]
- Size of the regurgitant orifice
- Afterload of the right ventricle
- Right ventricle diastolic compliance
- Duration of right ventricular diastole
According to 2014, ACC/AHA valvular heart disease guidelines the stages of severe pulmonary regurgitation are described as follows:[9]
| Stage | Definition | Pulmonary Valve
Anatomy |
Valve Hemodynamics | Hemodynamic Consequences | Symptoms |
|---|---|---|---|---|---|
| C,D | Severe PR |
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None or variable and dependent on the cause of PR and right ventricular function |
References
- ↑ Khavandi, Ali (2014). Essential revision notes for the cardiology KBA. Oxford: Oxford University Press. ISBN 978-0199654901.
- ↑ Curtiss, E I; Miller, T R; Shapiro, L S (1983). "Pulmonic regurgitation due to valvular tophi". Circulation. 67 (3): 699–701. doi:10.1161/01.CIR.67.3.699. ISSN 0009-7322.
- ↑ 3.0 3.1 Malviya A, Jha PK, Kalita JP, Saikia MK, Mishra A (2017). "Idiopathic dilatation of pulmonary artery: A review". Indian Heart J. 69 (1): 119–124. doi:10.1016/j.ihj.2016.07.009. PMC 5319124. PMID 28228295.
- ↑ 4.0 4.1 Sharma RK, Talwar D, Gupta SK, Bansal S (2016). "Idiopathic dilatation of pulmonary artery". Lung India. 33 (6): 675–677. doi:10.4103/0970-2113.192869. PMC 5112830. PMID 27891002.
- ↑ Segall, S.; Ritter, I. I.; Hwang, W. (1950). "A Case of Marked Dilatation of the Pulmonary Arterial Tree Associated with Mitral Stenosis". Circulation. 1 (4): 777–781. doi:10.1161/01.CIR.1.4.777. ISSN 0009-7322.
- ↑ Deb SJ, Zehr KJ, Shields RC (October 2005). "Idiopathic pulmonary artery aneurysm". Ann. Thorac. Surg. 80 (4): 1500–2. doi:10.1016/j.athoracsur.2004.04.011. PMID 16181901.
- ↑ 7.0 7.1 Bigdelian H, Mardani D, Sedighi M (2015). "The Effect of Pulmonary Valve Replacement (PVR) Surgery on Hemodynamics of Patients Who Underwent Repair of Tetralogy of Fallot (TOF)". J Cardiovasc Thorac Res. 7 (3): 122–5. doi:10.15171/jcvtr.2015.26. PMC 4586599. PMID 26430501.
- ↑ Chaturvedi RR, Redington AN (2007). "Pulmonary regurgitation in congenital heart disease". Heart. 93 (7): 880–9. doi:10.1136/hrt.2005.075234. PMC 1994453. PMID 17569817.
- ↑ Nishimura RA, Otto CM, Bonow RO, Carabello BA, Erwin JP, Guyton RA; et al. (2014). "2014 AHA/ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines". J Am Coll Cardiol. 63 (22): e57–185. doi:10.1016/j.jacc.2014.02.536. PMID 24603191.