Pathology of CVS
Tumours of the heart & pericardium:
Important points
The commenest malignant cardiac/pericardial tumor is metastatic carcinoma.
Atrial myxoma is commonest primary tumour.
Primary malignant cardiac/ pericardial tumours are rare.
Cardiac Myxoma
Commonest primary tumor.
90% in the atrium, 80 in the left atrium.
Morphology
Almost always single.
Most common site is fossa ovalis.
Size range from 1-10 cm.
Microscopicaly
Stellate multinucleated myxoma cells admixed with cells with endothelial,smooth muscle differentiation with or without fibroblastic differntiation.
Hemorrhage, poor organized thrombus and mononuclear infiltrate also present.
Metastatic tumors
12% of all fatal malignancy involve the heart
Lung ca.(scc)
Renal cell carcinoma.
Lymphoma.
Breast cancer.
Leukemia.
Melanoma.
Carcinoma of the liver.
Carcinoma of the colon.
Pathology of surgical and medical
cardiac intervention
Important points
Coronary artery bypass grafts undergo thrombosis, intemal proliferation and atheroma with luminal stenosis.
Coronary artery angioplasty may cause rupture, disssection, thrombosis, atheroembolism and restenosis.
Prosthetic valves may undergo structural failure (medical valves) or calcification (bioprosthetic valves), blockage by thrombus or scarring, thromboembolism, infection, paravlvular leakage, and may cause hemolysis..
Cardiac transplants may undergo rejection, infection and transplant accelerated coronary artery disease.
Pathology of coronary artery bypass graft
Venous and arterial vascular grafts are used to bypass narrowed coronary artery segment.
Venous grafts derived from leg veins are inserted into aorta and anastomosed distal to the coronary artery stenosis.
Arterial grafts are derived from internal mammary or radial arteries.
Complications of venous grafting
Luminal stenosis and occlusion
Thrombosis, atheroma formation and graft occlusion.
Complications of arterial grafting
The main problem in the arterial graft usually due to short segment.
Coronary artery angioplasty
Dilatation using a baloon catheter inserted percutaneously is an alternative form of revascularization for descrite coronary stenosis.
Angioplasty produces mechanical arterial distention with intimal tearing and medial disruption.
Complications of arterial angioplasty include:
Arterial rupture.
Dissection.
Thrombosis.
Atheroembolism.
Re-stenosis affect 1/3 of patient at 2 years and is due to intimal proliferation.
Pathology of valve prostheses:
Prosthetic valves is either mechanical or biological (porcine or human aortic valve leaflets).
Mechanical failure is caused by fatigue or obstruction to moving parts by scar tissue or thrombus.
Biological valves undergo cusp calcification after a number of years.
Thrombosis and systemic embolism, is a particular risk for pt. with mechanical valves who required anticoagulants.
Infective endocarditis occurs at a rate of around 1-6% per annum for prosthetic valves with mortality reaching 50% or more especially with early infection of a mechanical valve.
Large vegetations may occlude or impair valve function.
Haemolysis.
Pathology of cardiac transplantation:
Accepted treatment for end stage heart failure with 5-year survival reaching 75%.
In adults the commonest indications are ischemic heart disease and dilated cardiomyopathy.
After the post-operative period, most deaths occur in the first year due to infection.
Acute rejection is detected and monitored using histological assessment of regular heart biopsies with appropriate adjustment of immunosuppression.
The main cause of death caused by accelerated coronary artery disease.
MI affect 50% of transplanted hearts at 5 years.
Lymphoproliferative disorders.