instruction: how many patients whose procedure long title is excision or destruction of other lesion or tissue of heart, open approach and lab test fluid is pleural?
response: SELECT COUNT(DISTINCT demographic.subject_id) FROM demographic INNER JOIN procedures ON demographic.hadm_id = procedures.hadm_id INNER JOIN lab ON demographic.hadm_id = lab.hadm_id WHERE procedures.long_title = "Excision or destruction of other lesion or tissue of heart, open approach" AND lab.fluid = "Pleural"