Acute Renal Failure Following Coronary Angiography - Essay Example

Health Sciences and Medicine 10 March Acute Renal Failure Following Coronary Angiography Objective: This studyaims to assess the incidence of contrast-induced nephropathy after angiography and evaluate the risk factors in relation to the incidence and compare the result with other studies conducted on the topic, on an international level. Background: Contrast-induced nephropathy (CIN), is an increase in the baseline serum creatinine concentration of >25% or 44 mol/l. The incidence of CIN has not changed significantly in the last 20 years. It can be as high as 20% in high risk patients while it remains a rare instance in general population. It is also identified as the third major cause of hospital acquired acute renal failure. Method: This study is based on retrospective comparative evaluation and analysis. Demographic, cardiovascular risk factors, presenting and procedural characteristics etc collected for all 1567 patients who underwent PCI in 2011. 124 from the sample population were excluded out of 1567 patients because they underwent angiogram at a different time period. The laboratory parameters have also been obtained for the remaining 1443 patients. Subsequently, the patients who have unknown serum creatinine values have also been excluded (total number 1008 out of 1443). Thus, only 435 patients with documented creatinine have been included in the actual study. Routine hydration was performed. The primary outcome was change in serum creatinine 24 h post procedure.  Results: Out of 435 patients, 12.2% fulfilled the criteria for ARF, after coronary angiography. The incidence was 9% (decreased by 14) (n=39) when patients with baseline increased serum creatinine (>1.5 mg/dl) were excluded. A total of 321 (73.8%) were men and 114(26.2 %) were women. 14% of the women developed ARF, 28.3% of older age group (60 years old and above) had CIN (p value .165). Out of 53 patients, 69.8% were with hypertension, the same incidence among those with Hypercholesterolemia and multi-vessels diseases. Patients contributing 56.6% (p value .515) of the incidence had a history of diabetes mellitus, and 20.8% (n=11) with renal failure. A total of 16 Patients who received less 0.5 mg/dL (>44 μmol/L) or 25%” (Aredia) above baseline within 48 hours after contrast administration (3) (4). The increase in serum creatinine concentration is a temporary permanent in most cases or that it things minor changes in renal function, whereas contrast-induced acute renal failure may result in increased indisposition and in the mortality extending from 1 to 5 years rates in selected at-risk populations(2)(5)(6)(11). The incurred expenditure is very high, as it involves the use of most modern equipments in the hospital. Generally, CIN patients remain in hospital for 10 to 15 days. The need of dialysis increases 10% to 15%, and there are also delays in scheduling treatment for the future (7). Contrast-induced nephropathy (CIN) was first recognized more than 56 years ago (8). Radiographic Contrast Media is responsible for 11% of the cases of hospital-acquired renal deficiency, and this is the “third most common cause of renal failure after impaired renal perfusion” (Mehran & Nikolsky) consequent to the use of nephrotoxic medications (10) (9),(12). Among all procedures utilizing contrast media, coronary angiography and percutaneous coronary interventions (PCI) are rated as the highest forms of treatment in CIN on occasions of cardiac intervention, CIN has on added attention(13)( 4) . The annual overall population growth rate is 1.1%, but the growth rate is not uniform at all levels. It increases in the age growth between 60 and 80 years to 2.6%, and reaches 3.9% in individuals above 80 years (14). The incidence has been calculated to be more than 20% to 30% in patients who have diabetes mellitus, congestive heart failure, chronic renal failure and old age disabilities (2) (15) (6) (7) (16). Furthermore, females also serve as a major influencing factor.(5)(17). Unfortunately, doctors who handle the cases many physicians who are not aware of the risks involved in CIN (18) (19). As there is a tremendous increase in the consultant methodologies associated with the use of contrast media nephrologist can effectively diagnose and reduce the incidence of CIN by imparting information to other physicians regarding the far reaching consequences it can create in patients (12). As there is immense risk in administering contrast media, prime importance should be given to preventative measures, identification of patients at high risk for the development of CIN and equipping physicians involved in the care of these patients (3). Otherwise, the consequences would be disastrous. Specific Aims: The Proposed Research will Achieve the Following Goals: (1) Asses the incidence of contrast-induced nephropathy following cardiac angiography, and compare the results with the international data. (2) The presence of a high incidence CIN following coronary angiography could be used to highlight the importance of getting the right form of diagnosis and also to guide further diagnosis and preventive measures. (3) Correlate the incidence with Mehran risk score and each risk factors. Method: SMBSAK Cardiac Centre, Defense Force Hospital Cardiac Centre serves as choice for research because it is the only firm in the country where one can identify pre procedure data and round the clock post procedures follow up. In times up cardiac catheterization, extent of difference is usually larger than the amount used for computed tomography and angiography scan. That is the reason for choosing cardiac catheterization unit. A deep study on the part related cases was carried out where demography (including age, sex, weight and height), smoking status, co-morbidities (diabetes mellitus, hypertension, hypercholesterolemia, peripheral vascular diseases, cardiogenic shock, chronic renal failure and congestive heart failure) angiographic (multi-vessels, number of PCI and the use of intra-aortic balloon pump), pervious CABG and myocardial infarction were inspected. Reports from BDF hospital’s cardiac catheterization laboratory indicate that 1567 patients did PCI in 2011. Of these, some had undergone PCI the previous December whereas others did it in January 2012, and therefore, 124 patients were not included. Hematologic (including hematocrit) and biochemical (Fasting glucose, HBA1c, serum creatinine pre and post procedure and eGFR) laboratory parameters for all 1443 were received from DFH software (AL-Care). The use of cardiac catheterization laboratory A and B database for 1443 facilitated in getting a contrast amount. The use of creatinine clearance was estimated for 1443 by the Cockcroft-Gault (20) equation. Those with undetected serum creatinine pre procedure (N=55) and post procedure (N=953) or both values were not included (total number 1008 out of 1443). Therefore, 435 patients with recorded pre and post procedure serum creatinine were inducted into the study. No sub divisions in patients (for example, those with cardiogenic shock, renal failure) were left out. Routine hydration was carried out with 1 ml/kg/h of half-normal saline for at least 6 h before PCI and 18 to 24 h after PCI. In most of the cases, Visipaque (iodixanol) was used as the contrast agent. The difference in creatinine concentration was calculated using the most recent measurement with the angiogram as the baseline. The basic result was a change in serum creatinine 24 h post procedure. The secondary result was finding of relationship between the incidences of contrast induced renal failure and the risks involved in it. Result: Of the 435 patients, 53(12.2%) fulfilled the criteria for ARF, following coronary angiography. The incidence of this complication was 9% (decreased by 14) (n=39) when patients with baseline increased serum creatinine (>1.5 mg/dl) were not included. A total of 321 (73.8%) were men (p value =.721) and 114(26.2 %) were women. 14% of the women had ARF, while 11.2% of the male had ARF. 28.3% of the incidence happened among those the age growth of 60 and 69 (p value .165). Of the incidence (n=53), 56.6% (n=30)(P value .515)of them had history of diabetes mellitus, 69.8% (n=37) (p value .748)with hypertension, 69.8 %( n=37) (p value .669)with Hypercholesterolemia, 35.8% (n=19) (p value .318), smoker20.8% (n=11)(p value .021) with renal failure and 81.8% (n=9) of those had previous dialysis, 7.5% (n=4) had previous MI, 7.5% (n=4) had previous CABG, 3.8% (n=2) with peripheral vascular disease, 10 (18.88%) had previous PCI, 41.5%( n=22) (p value =.001)had low baseline eGFR and 2 (3.8%) had been treated with an IABP. 37 (69.8% ) Patients with multi-vessels disease developed CIN
10 (18.88 %) with one vessel disease developed CIN and 5 (9.4 %) with no vessel disease. 13 (24.5%) Patients who were treated with PCI for multi- vessel, 23 (43.4 %) for one vessels and 11 (20.8%) where PCI wasn’t applied as procedure. Of a total of 435 patients, 76 (of those, 6 had CIN) were excluded for inability to calculate MRS. In relation to Mehran risk scores, 47 patients (all with CIN) were further categorized into four groups (figure 1). Patients who had CIN were grouped based on contrast volume (figure 2). Discussion: The results indicate that contrast-induced nephropathy develops complication or angiography and in patients who did with co-morbidities; even in patients with normal baseline renal function. While, in patient without risk factors the incidence was rare (0.6%).In other studies the incidences were rare (≤2%) in the overall population, but the higher could reach 20% in high-risk groups which confirm our result (2) (15) (6) (7) (16). The highest rates of risk factors in the incidence patients were hypertension and hypercholesterolemia yet the results were statically unimportant. Moreover, number of patients with diabetes mellitus was more than half of the incidence which indicate that diabetes mellitus represent a significant risk factor. The incidence of CIN in diabetic patients in other studies varies between 5.7 to 29.4%29, 30. The study it was within this international range (12.6%) and limited also was statically insignificant. The increase in the percentage could be due to high prevalence of diabetes, hypertension and hypercholesterolemia in the general population and the ability of these diseases “to cause a broad spectrum of cardiovascular diseases that require radiological procedures using CM” (Mehran & Nikolsky). Smoking is causes in causing cardiovascular disease and it is found out the one third of CIN patients were smokers. This is also statically insignificant. In further studies the “incidence of CIN in patients with underlying chronic kidney disease is extremely high, ranging from 14.8 to 55%” (Mehran & Nikolsky). In the study it is within this range, but not at the highest. In relation to other risk factors also it was statically insignificant. At the same time, a very high percentage of patience with incidence renal failure did renal dialysis. Numerous studies provide proof for the fact old age is an independent predictor of CIN 34, 35, 36. It could be connected with changes in renal function with elders (37). In the research the highest incidence was between 60 and 69 and it is statically insignificant. Our findings also confirm that female gender is a very influential factor. This may be connected with the effects of ovarian hormones on the renal blood flow and renin-angiotensin system [38] . Few incidences had previous MI, previous CABG and previous PCI. The study revealed 24.5% with multi-vessels PCI developed CIN, however higher incidence in those with one vessels PCI also it was statically insignificant .In contrast to another study where it showed higher incidence among those with multivessel PCI due to high volume of contrast begin used(39)(40). Very high incidence (69.8%) was among those with multivessels disease , comparing to those with one vessel disease 18.88% developed CIN also it was statically insignificant . a study showed significant renal artery stenosis due to atherosclerosis in patients with >2 coronary lesions(41)(42).Our results revealed , high incidence of CIN (11.3 % ) in those who received low contrast amount (< 100 ml) similar finding in other studies where they stated  that even low doses of contrast (< 100 ml) can cause permanent renal failure and the less contrast amount the lower incidence(39). The study also reveals that CIN developed in “every fifth, fourth, and second patient who received 200–400, 400–600, and 4600ml of CM, respectively” (Mehran & Nikolsky). Yet, the results showed an exponential increase in the incidence with higher contrast volume (301-400 ml) causing relatively low incidence (10.5 %). The study concluded, there was no association between the total volume and an early creatinine increase (43). It also showed low incidence of CIN in those who high contrast dose (>100 ml) and vice versa. However this results was statistically insignificant (44) and so our result .Also, there are no prospective studies that prove the relation between contrast volume and CIN (45). “Apart from the known unfavorable combination of diabetes and renal insufficiency” (Mehran & Nikolsky) having two or more risk factors for CIN also has an additive influence on the incidence of CIN. Using  Mehran  risk score for CIN would help in assessing the risk , based on “eight variables (hypotension, intraaortic balloon pump, congestive heart failure, chronic kidney disease, diabetes, age >75 years, anemia, and volume of contrast)” (Mehran & Nikolsky). The occurrence of CIN was found to be 7.5–57.3% for a low (X5) and high (X16) risk score, respectively(39)(40)(46)(47). In one study, for example, CIN rarely occurred in patients without risk factors, and in 420% of the patients with many risk factors (48). In the present study, we stratified the patients who had CIN based on 7 variables. The variables are: 1) patient characteristics (i.e., > 75 years, diabetes mellitus, chronic congestive heart failure, anemia, and chronic kidney disease); and 2) procedure characteristics (i.e., the use of IABP or increasing volumes of contrast media). This study showed 9.2%- 24.2% for a low(X5) and very high (X16) risk score, respectively. This is extremely important because Once CIN is established, only supportive care can be provided until renal function restores; and it could result in transiently or even permanently kidney damage. Also, its associated with a prolonged hospitalization and unfavorable prognosis (39). And thats why, the only main method to mange “this complication is its prevention. We believe that adequate risk assessment before PCI offers a greater opportunity to do so” (Cardiol). Limitations can be summarized as follows: 1. The data were collected retrospectively by dependent monitors. 2. Due to limited availability of data, we could not find all variables for the whole sample e.g. HbA1c for diabetic patients weren’t measured in short period either pre or post procedural. So we used the most recent data available.  3. The use of the most recent creatinine measurement was before the angiogram as the baseline. 4. The sample was initially 1443 patients and it decreased to 435 due to the absence of data on serum creatinine 24 h after angiogram procedure. This could significantly underestimate CIN incidence.  5. “The absence of data on serum creatinine later than 48 h after PCI in the present study might result in the slight underestimation of CIN. However, it is not sure that a delayed creatinine elevation in patients without a significant rise within 48 h after PCI may be relevant clinically” (Cardiol). Conclusions: The incidence of contrast-induced nephropathy after angiography is high in patient with hypertension, hypercholesterolemia, diabetes, chronic renal failure and other risk factors. Thus one should be aware of the consequences, recognize risk group, withholding potentially nephrotoxic agents and perform preoperative assessment with a focus on the volume of contrast. Patients at risk group must be definitely do renal function testing, continuation of post-procedure hydration and newer preventive strategies of renal protection during angiography. P- values and OR and CI P-value OR 95% C.I for OR Lower Upper Age (>75) .165 3.577 .592 21.614 Gender(Male) .721 .837 .315 2.223 Diabetes mellitus .515 .718 .264 1.949 Hypertension .748 1.233 .344 4.417 Hypercholesterolemia .669 1.332 .357 4.972 Smoking history .318 .623 .246 1.577 Renal failure .021 .070 .007 .670 Anemia .184 .497 .177 1.395 eGFR .001 eGFR( Read More