Introduction

By improvement in both surgical and percutaneous revascularization techniques, the treatment of coronary artery disease has evolved and excellent results have appeared.

These patients with a chronic stable Angina need not worry since almost all will be managed by medical therapy, however those in need of coronary artery bypass surgery or percutaneous coronary intervention will be of our interest, especially those undergoing surgery⁽¹⁾. One of the greatest risk post operatively is cardiac tamponade. And in order to prevent or minimize cardiac tamponade we strongly recommend doing partial left pericarditomy incision to relieve the heart post operatively of any pressure effect that the blood or clots may exert.

Methods

We followed the cases of a surgeon with routine partial pericardiotomy during an eleven year follow up on his 3200 cases of CABG and compared with the rest of his colleagues at a large Metropolitan 600 bed Heart Center in Tehran, Iran with about 20016 cases of CABG from March 1, 2004 to May 30, 2015.

The data were collected retrograde by our cardiac surgery registry (Table I, II). Those cases undergoing CABG at our hospital, irrespective of the use of CPB, are fully heparinized, namely, receiving 300 unit per-kilogram body weight of heparin, irrespective of whether they are having on-pump or off-pump surgery. All those cases of having mitral valve surgery and or repair, resection of a ventricular aneurysm or other surgical procedure along with CABG’s were excluded and some detail methods of collecting data have been described in detail by Wynne-Jones⁽⁶⁾.

Table I:  Heart Hospital Registery

Table II: Procedural techniques

The primary outcome measure of our study was re-exploration for cardiac tamponade, which was deferred as collection of clot and bleeding that required surgical re-exploration after arriving at I.C.U from open heart surgery. The decision to take patient back to O.R. was made by cardiac surgical fellow responsible based on the protocol promulgated by Kirklin and Barrat-Boyes⁽⁷⁾ and table III. Although slight modification has been made regarding the patient’s vital signs.

Table III: Chest Drainage Criteria for Reoperation

^aReoperation is advisable if the patient has bled the amount indicated in any 1 hour (column 1), the lesser amount in column 2 during each of any 2 successive hours, or the still smaller amount (Column 3) in each of any 3 successive hours.

^bReoperation is advisable, if by the end of the fourth or fifth postoperative hour, the patient has bled in total the amount indicated.

The criteria are as follows: ⁽¹⁾ drainage of more than 500 ml. during the first hour, more than 400 ml. during each of the first 2 hours, more than 300 ml. during each of the first 3 hours, or more than 1000ml. in total in the first 4 hours ⁽²⁾ obvious signs of cardiac tamponade; ⁽³⁾ sudden massive bleeding;  ⁽⁴⁾ excess bleeding despite correction of coagulopathies, and  ⁽⁵⁾ cardiac arrest in a patient who continues to bleed.

The results that were collected after re-exploration for cardiac tamponades and bleeding are listed in table 4. All patients that were followed especially for sternal wound infections were in accord with the published evidence-based guidelines by the Center for Disease Control and Prevention (CDCP)⁽⁸⁾.

Also a group leading by Kuvin JT ⁽²⁾ analyzed retrospectively 4561 consecutive patients undergoing open heart surgery, and those with clinical suspicion of pericardial effusion following surgery were further evaluated by transthoracic or trans esophageal echocardiography and only 48 (1%) had evidence of moderate or large pericardial effusion of whom 37 (74%) had evidence of pericardial tamponade (PT). Of course only 24% of above cases had CABG while the rest had some valvar involvement such as valve replacement or repair. He reported one in hospital death due to pericardial tamponade (PT).

So he concluded that pericardial tamponade following open heart surgery was more common with any valvar manipulation along with CABG⁽²⁾.

A patient with CAD has athermanous lesions in his coronaries, impeding blood flow to his cardiac muscles. Therefore by doing bypass surgery it will supply extra flow to the region.

Now one of the complication post operating is bleeding. Approximately 30 percent of patients require a blood transfusion after CABG. Patients with heavy bleeding that requires reoperation often need multiple blood transfusions and may stay longer in the intensive care units.

Only about 2 percent of those will require surgery to stop excessive bleeding ⁽³⁾.

One factor that increases the risk of bleeding post CABG is taking aspirin prior to surgery. Plavix (Clopidogrel) and ibuprofen are generally discontinued for several days prior to coronary surgery. Those on warfarin should consult their surgeon prior to surgery ⁽³⁾.

Other study by Floerchiger et al ⁽⁴⁾ revealed a bigger pool of patients in need of surgical intervention for cardiac tamponade. A total of 12 cases (44%) out of 25 patients after open heart surgery were taken for surgical intervention for bleeding. By using CT imaging as a supplemental procedure provided a rapid diagnostic reliability in patients with delayed cardiac tamponade since diagnostic accuracy of transthoracic echocardiography is limited in patients after open heart surgery⁽⁴⁾.

There was a case of late cardiac tamponade of about 400 days post-operatively that drained 1350 ml in total. This 48 year old male had undergone quadruple CABG, with history of three episodes of near fainting and collapsed after taking his evening dose of Atenolol 50mg. There was no history of trauma. An echocardiogram showed some fluid, so by catheter drainage some 750 ml serosanguin fluid was drained with difficulty and some improvement was achieved. Yet in day two, again the echo revealed more re-accumulation of fluid around posterolateral aspect of left ventricle and further 200 mls of blood were aspirated. On day four more than 400ml was shown and it was evacuated manually. So on day seven patient recuperated well and new echo data showed minimal residual fluid there. Patient left the hospital on day 9. A total of 1350 ml were aspirated ⁽⁵⁾.

Now if we had the pericardial wall opened all the way to near left phrenic nerve bundles, we would have avoided this collection of fluid around the heart and would have avoided catastrophic outcomes. We have clearly demonstrated these good results at our center by analyzing the database available (Shahid Rajaie Heart Data Base, Tehran, Iran), Table IV.

Table IV: Outcomes in propensity- Matched Groups

Hospital mortality was defined as death within the same hospital admission regardless of cause. Renal failure was defined as rise of createnin  above 1.5 (Createnin level greater than 200 mmol/L) or Patients requiring dialysis.

Another way of obtaining a safe and good results post CABG is early re-exploration for bleeding. We at Shahid Rajaie Heart Hospital have developed a protocol of early re-exploration of post CABG cases once the total drainage reaches of about 1000 ml.

Some factors affect our decision for early re-exploration post operatively, namely having a rare blood group, an unstable hemodynamics even as getting massive doses of ionotropes, and finally deranged lab data especially on coagulations such as INR, prothrombin, Partial Thromboplastin Time (PTT) and number of platelets.

Patients requiring re-exploration for bleeding and tamponade were propensity-matched with those cases of bleeding in need of exploration, yet had not partial left pericardiectomy dove. To do this, logistic regression ⁽⁹⁾ was used to develop a propensity score for re-exploration for early bleeding for all patients of CABG whether or not they had partial pericardiotomy ⁽¹⁰⁾. The propensity score was constructed using all the variables listed in table V.

Table V: Propensity-Matched Groups of Patients

Patients re-explored were matched with those not having PLP who had our identical 5-digit propensity score. If this could not be done, we would reduce one score each time, until it matched ^{(11, 12)}.

Results

Overall, of the 3200 patients 74 were re-explored while in those of 20016 cases about 625 were taken to OR to control bleeding and clot removals.

The incidence of re-exploration has increased from 2.1% in those with partial left pericardiotomy (PLP) to almost 3.3% in those cases not doing it.

Of 74 cases of re-exploration following PLP, the primary indication was bleeding (66).

Other indications were 8 tamponade and 2 cardiac arrests. The major sites of bleeding were as follows: 38 were graft/anastomosis, 30 sternal/left internal mammary artery bed, 4 extra-pericardial, and 2 were cannulation sites.

The median time to take patient to operating room was 8.5 hours after arrival at I.C.U and median blood loss was 1480 ml before re-exploration. 6 patients required more than one re-exploration.

The results of multivariate logistic regression analysis (Table VI) showed that non-elective surgery (P=0.022) and more grafts (P=0.035) and finally increased age (P=0.041) were all independent predictors of re-exploration for bleeding and tamponades.

Table VI: Multivariate Risk Factors for Tamponade and bleeding re-exploration

It is worth to mention that no association was found between re-exploration for bleeding and preoperative aspirin and heparin use in off-pump CABG, although for on pump CABG cases had higher proportion of re-exploration by those on Aspirin (P-0.004) and aspirin/heparin (P=0.001).

The relation between the time for re-exploration for bleeding and post operative outcomes are shown in Table VII.

Table VII: Time to Re-exploration and postoperative outcomes

Conclusion

We believe that most cases of bleeding after open heart surgery have a surgical cause, and hence, there is a stronger recommendation for early exploration of those patients who continue to bleed after coming to I.C.U. Also most studies have found increased risk in older patients, longer CPB times, greater number of distal anastomosis, dialysis dependent renal failure and the use of internal mammary artery ^(13-16).

So one of the greatest risk factors for re-exploration for bleeding after open heart surgery is cardiac tamponade and delay in re-exploration. Patients in need of re-exploration are at higher risk of complications if we have not opened up the left pleural space via partial left pericardiotomy to allow space for blood and clots to drain into left pleural space therefore relieve the heart of possible pressure effect of clots and therefore prevent a catastrophic tamponade and if the time for re-exploration is delayed.

We strongly urge the in-house policies that promote opening up the left pleural space via partial left pericardiotomy to near the left phrenic nerve and also prompt return to the operating room for re-exploration for bleeding.

References

1. S, Cutlip. D, Aroesty J. et al. Early complications of coronary bypass graft surgery. Literature review current through July 2015. www.uptodate.com
2. Jt, Harati NA, Panadian N6; Post operative cardiac tamponade in modern surgical era. Ann Thorac Surg 2002 Oct; 74(4):1148-53.
   CrossRef
3. Aroesty J. et al. Patient information: Coronary artery bypass graft surgery (Beyond the basis), uptodate.com March 27, 2014.
4. Floerchinger B, Camboni D, Schopka S, et al. Delayed cardiac tamponade after open heart surgery in supplemental CT imaging reasonable? J Cardiothoracic Surgery 2013, 8:158.
   CrossRef
5. Azzopandi E, Farrugia P, et al. Massive late post-coronary arterial bypass graft tamponade. ISPub.com 2007 Vol. 4, no 2.
6. Wynne-Jones K, Jackson M, et al. North west Regional cardiac surgery Audit Steering Group. Heart 2000:84;71-8.
   CrossRef
7. Kirklin JW, Barrat-Boyes B6, Cardiac Surgery New York: John Wiley and sons, 1993, 222-4.
8. Mangram AJ, Horan TC, Pearson ML for the Hospital Infection Control Practices Advisory Committee. Guidelines for prevention of surgical site infection, 1999. Infect control Hosp Epidemiol 1999, 20:247-78.
   CrossRef
9. Hosmer JA, Lemeshow S. Applied Logistic regression. New York John Wiley and Sons 1989.
10. Blackstone E, Comparing apples and oranges. J Thorac Cardiovascular Surg 2002; 123;8-15.
    CrossRef
11. Hanley JA, McNeil BJ: The meaning and use of the area under a receiver operating characteristics (ROC) curve. Radiology 1982; 143:29-36.
    CrossRef
12. Pansons LS, Reducing bias in a propensity score matched-paired sample using greedy matching techniques. Proceedings of the Twenty-Sixth Annual SAS Users Group International Conference Cary, NC: SAS institute 2001.
13. Dacey LJ, Munoz JJ, Baribeau YR et al. Re-exploration for hemorrhage following CABG, incidence and risk factors. Arch Surg 1998; 133:442-7.
    CrossRef
14. Sellman M, Intonti MA. Et al. Reoperation for bleeding after CABG during 25 years. Eur J Cardiology Surg. 1997:11:521-7.
    CrossRef
15. Maulton MJ, Creswell LL, Mackey ME et al. Re-exploration for bleeding is a risk factor for adverse outcomes after cardiac operations. J Thorac Cardiov. Surg. 1996:111:1037-46.
16. Despotis GJ, Filos KS, Zoys TN et al. Factors associated with excessive post operative blood loss and hemostasis transfusion requirments. A multivariate analysis in cardiac surgical patients. Anaesth. Analg 1996:82:13-21.