A system and method for determining a pH level of blood in a vessel of a patient including a flexible elongated member configured and dimensioned for insertion in the vessel of the patient, a sensor positioned at the distal portion of the elongated member, and a connector connecting the elongated member to an indicator. The sensor measures the pH level of blood downstream of the blood clot. A system and method are also provided for determining a density of a blood clot in a vessel of a patient for subsequent selection of a treatment method. The system includes a sensor positioned at the distal portion of the elongated member, and a connector connecting the elongated member to an indicator, wherein the sensor determines the density of the blood clot and the indicator provides an indication of the density of the clot.
