Brief Answer: Seek a cardiologist Detailed Answer: Good day mr XXXX Thank you for asking. Hypotension is a multi dimensional approach and it can have many aetiologies.It could be posture related, Diet related (Post prandial), it could be cardiac issue like valvular disorders like Aortic regurgitation, It could be endocrinological aspect like addison's or electrolytes derangement, it could be geriatric age related with lung compromise like pneumonias etc, It could be diastolic perfusion issues and it could be some conduction issues. Irrespective of the aetiology you need a cardiologist to sort it out and an endocrinologist to rule out hormonal causes like Addison's or Hypokalemia etc. Now AHA guidelines make a cut off point of 55 mm hg as too low for diastolic blood pressure and systolic less than 85. As lower systolic than that start compromising renal perfusion and result in shock and renal failures etc. Now your case of bronchogenic carcinoma and cardiac procedure history with such a geriatric age limits make you a very likely candidate for a cardiac issue and a strict monitoring is recommended to observe and monitor your vitals. Hope it helps XXXX. Take good care of yourself and seek help. Don't forget to close the discussion please. Regards Khan

---