A hemoglobin drop without evidence of hemorrhage may reflect the preprocedural preparations or procedural techniques. Patients that have been NPO prior to the procedure may start out relatively hypovolemic and hemoconcentrated. Additionally, some institutions aggressively hydrate their catheterization patients prior to diagnostic and interventional procedures to counter the effects of sedative/vasodilatory medications and renal protection for contrast induced nephropathy. Nitrate medications used during the procedure can cause vasodilation, which expands the vascular space. These combined effects may lead to a post-procedural dilutional change in the hemoglobin that does not represent any true hemorrhage (BARC 0, see table below)
During the procedure itself, there are plenty of opportunities for blood loss. Blood draws for frequent ACT checks including the blood waste from the manifold (20 mL) prior to the ACT blood draw. There is also blood loss from the arteriotomy, catheter flushing/leakage. This is true blood loss which is often not tracked well, may or not but can exaggerate the post-procedural blood loss which complicates evaluating for hemorrhage complication.
Even if the hemoglobin drop does not represent a complication hemorrhage (BARC 1), it may still be clinically significant depending of the initial hemoglobin (BARC 2). Shortness of breath or ischemic chest pain from a dilutional anemia, may need to be treated with diuretics. Transfusion could be called for but may complication volume overload in patients with reduced ventricular function.
The Bleeding Academic Research Consortium (BARC) has defined a classification scheme for catheterization bleeding (see table below). It was originally used to standardize research reporting, but has been expanded its use for structured complications reporting.
|BARC Bleeding Definitions|
|Type 0||No bleeding|
|Type 1||Bleeding that is not actionable and does not cause the patient to seek treatment|
|Type 2||Any clinically overt sign of hemorrhage that “is actionable” and requires diagnostic studies, hospitalization, or treatment by a healthcare professional|
|Type 3||a. Overt bleeding plus hemoglobin drop of 3 to < 5 g/dL (provided hemoglobin drop is related to bleed); transfusion with overt bleeding
b. Overt bleeding plus hemoglobin drop < 5 g/dL (provided hemoglobin drop is related to bleed); cardiac tamponade; bleeding requiring surgical intervention for control; bleeding requiring IV vasoactive agents
c. Intracranial hemorrhage confirmed by autopsy, imaging, or lumbar puncture; intraocular bleed compromising vision
|Type 4||CABG-related bleeding within 48 hours|
|Type 5||a. Probable fatal bleeding
b. Definite fatal bleeding
Minimizing the procedural blood losses should be priority. This can include using radial artery access. Routine hydration is probably not indicated unless patient is clearing hypovolemic, especially if there is reduced ventricular function.
In all cases, a hemoglobin drop after PCI should prompt a thorough investigation for hemorrhage before calling it dilutional or insignificant, especially with femoral access.