Your history of difficulty starting urine, weak flow, needing to strain, prolonged emptying and previous episodes requiring catheterization needs proper evaluation. Since these symptoms developed after urinary catheterization, a narrowing of the urethra (urethral stricture) is one possibility, although prostate enlargement, bladder-neck obstruction or reduced bladder contractility can also cause similar symptoms.
Next Steps
I would recommend a urological evaluation with uroflowmetry and post-void residual (PVR) urine measurement. Depending on the findings, ultrasound and further assessment of the urethra/prostate may be required.
You can share your uroflowmetry report, ultrasound/KUB-prostate report, PVR value, urine test and current medicines, particularly the medicines started after your angioplasty. These details will help in understanding the cause of your difficulty in passing urine.
An individualized homoeopathic approach can be considered alongside appropriate evaluation, particularly for your associated urinary symptoms, but treatment should be based on the underlying cause rather than simply trying to increase the urine flow.
Health Tips
Please do not strain forcefully to pass urine or delay medical attention if you become unable to urinate. Acute urinary retention requires prompt bladder drainage.
Given your cardiac history and previous catheterization, I would recommend not postponing the urological assessment. If you currently cannot pass urine, develop severe lower-abdominal pain/swelling, fever or vomiting, seek urgent medical care.